diff --git a/.rubocop.yml b/.rubocop.yml
index 671d371d..3675ec84 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -54,4 +54,6 @@ FormatString:
 CaseIndentation:
   IndentWhenRelativeTo: end
 TrivialAccessors:
-  ExactNameMatch: true
\ No newline at end of file
+  ExactNameMatch: true
+PerceivedComplexity:
+  Enabled: false
\ No newline at end of file
diff --git a/middleman-core/features/collections.feature b/middleman-core/features/collections.feature
new file mode 100644
index 00000000..5020c147
--- /dev/null
+++ b/middleman-core/features/collections.feature
@@ -0,0 +1,145 @@
+Feature: Collections
+  Scenario: Lazy query
+    Given a fixture app "collections-app"
+    And a file named "config.rb" with:
+      """
+      articles1 = collection :articles1, resources.select { |r|
+        matcher = ::Middleman::Util::UriTemplates.uri_template('blog1/{year}-{month}-{day}-{title}.html')
+        ::Middleman::Util::UriTemplates.extract_params(matcher, ::Middleman::Util.normalize_path(r.url))
+      }
+
+      everything = resources.select do |r|
+        true
+      end
+
+      def get_tags(resource)
+        if resource.data.tags.is_a? String
+          resource.data.tags.split(',').map(&:strip)
+        else
+          resource.data.tags
+        end
+      end
+
+      def group_lookup(resource, sum)
+        results = Array(get_tags(resource)).map(&:to_s).map(&:to_sym)
+
+        results.each do |k|
+          sum[k] ||= []
+          sum[k] << resource
+        end
+      end
+
+      tags = everything
+          .select { |resource| resource.data.tags }
+          .each_with_object({}, &method(:group_lookup))
+
+      class Wrapper
+        attr_reader :stuff
+
+        def initialize
+          @stuff = Set.new
+        end
+
+        def <<((k, v))
+          @stuff << k
+          self
+        end
+      end
+
+      collection :wrapped, tags.reduce(Wrapper.new, :<<)
+
+      set :tags, tags # Expose to templates
+
+      collection :first_tag, tags.keys.sort.first
+      """
+    And a file named "source/index.html.erb" with:
+      """
+      <% collection(:articles1).each do |article| %>
+        Article1: <%= article.data.title %>
+      <% end %>
+
+      Tag Count: <%= collection(:wrapped).stuff.length %>
+
+      <% config[:tags].value.each do |k, items| %>
+        Tag: <%= k %> (<%= items.length %>)
+        <% items.each do |article| %>
+          Article (<%= k %>): <%= article.data.title %>
+        <% end %>
+      <% end %>
+
+      First Tag: <%= collection(:first_tag) %>
+      """
+    Given the Server is running at "collections-app"
+    When I go to "index.html"
+    Then I should see 'Article1: Blog1 Newer Article'
+    And I should see 'Article1: Blog1 Another Article'
+    And I should see 'Tag: foo (4)'
+    And I should see 'Article (foo): Blog1 Newer Article'
+    And I should see 'Article (foo): Blog1 Another Article'
+    And I should see 'Article (foo): Blog2 Newer Article'
+    And I should see 'Article (foo): Blog2 Another Article'
+    And I should see 'Tag: bar (2)'
+    And I should see 'Article (bar): Blog1 Newer Article'
+    And I should see 'Article (bar): Blog2 Newer Article'
+    And I should see 'Tag: 120 (1)'
+    And I should see 'Article (120): Blog1 Another Article'
+    And I should see 'First Tag: 120'
+    And I should see 'Tag Count: 3'
+
+  Scenario: Collected resources update with file changes
+    Given a fixture app "collections-app"
+    And a file named "config.rb" with:
+      """
+      collection :articles, resources.select { |r|
+        matcher = ::Middleman::Util::UriTemplates.uri_template('blog2/{year}-{month}-{day}-{title}.html')
+        ::Middleman::Util::UriTemplates.extract_params(matcher, ::Middleman::Util.normalize_path(r.url))
+      }
+      """
+    And a file named "source/index.html.erb" with:
+      """
+      <% collection(:articles).each do |article| %>
+        Article: <%= article.data.title || article.source_file[:relative_path] %>
+      <% end %>
+      """
+    Given the Server is running at "collections-app"
+    When I go to "index.html"
+    Then I should not see "Article: index.html.erb"
+    Then I should see 'Article: Blog2 Newer Article'
+    And I should see 'Article: Blog2 Another Article'
+
+    And the file "source/blog2/2011-01-02-another-article.html.markdown" has the contents
+      """
+      ---
+      title: "Blog3 Another Article"
+      date: 2011-01-02
+      tags:
+        - foo
+      ---
+
+      Another Article Content
+
+      """
+    When I go to "index.html"
+    Then I should see "Article: Blog2 Newer Article"
+    And I should not see "Article: Blog2 Another Article"
+    And I should see 'Article: Blog3 Another Article'
+
+    And the file "source/blog2/2011-01-01-new-article.html.markdown" is removed
+    When I go to "index.html"
+    Then I should not see "Article: Blog2 Newer Article"
+    And I should see 'Article: Blog3 Another Article'
+
+    And the file "source/blog2/2014-01-02-yet-another-article.html.markdown" has the contents
+      """
+      ---
+      title: "Blog2 Yet Another Article"
+      date: 2011-01-02
+      tags:
+        - foo
+      ---
+
+      Yet Another Article Content
+      """
+    When I go to "index.html"
+    And I should see 'Article: Blog3 Another Article'
+    And I should see 'Article: Blog2 Yet Another Article'
diff --git a/middleman-core/features/console.feature b/middleman-core/features/console.feature
index c3400e3b..1bd55809 100644
--- a/middleman-core/features/console.feature
+++ b/middleman-core/features/console.feature
@@ -1,8 +1,9 @@
 Feature: Console
 
   Scenario: Enter and exit the console
-    Given I run `middleman console` interactively
-    When I type "puts 'Hello from the console.'"
+    Given a fixture app "large-build-app"
+    When I run `middleman console` interactively
+    And I type "puts 'Hello from the console.'"
     And I type "exit"
     Then it should pass with:
     """
diff --git a/middleman-core/features/paginate.feature b/middleman-core/features/paginate.feature
new file mode 100644
index 00000000..9338e019
--- /dev/null
+++ b/middleman-core/features/paginate.feature
@@ -0,0 +1,204 @@
+Feature: Pagination
+  Scenario: Basic configuration
+    Given a fixture app "paginate-app"
+    And a file named "config.rb" with:
+      """
+      articles = resources.select { |r|
+        matcher = ::Middleman::Util::UriTemplates.uri_template('blog/2011-{remaining}')
+        ::Middleman::Util::UriTemplates.extract_params(matcher, ::Middleman::Util.normalize_path(r.url))
+      }
+
+      articles.sort { |a, b|
+        b.data.date <=> a.data.date
+      }.per_page(5) do |items, num, meta, is_last|
+        page_path = num == 1 ? '/2011/index.html' : "/2011/page/#{num}.html"
+
+        prev_page = case num
+        when 1
+          nil
+        when 2
+          '/2011/index.html'
+        when 3
+          "/2011/page/#{num-1}.html"
+        end
+
+        next_page = is_last ? nil : "/2011/page/#{num+1}.html"
+
+        proxy page_path, "/archive/2011/index.html", locals: {
+          items: items,
+          pagination: meta,
+          prev_page: prev_page,
+          next_page: next_page
+        }
+      end
+
+      def get_tags(resource)
+        if resource.data.tags.is_a? String
+          resource.data.tags.split(',').map(&:strip)
+        else
+          resource.data.tags
+        end
+      end
+
+      def group_lookup(resource, sum)
+        results = Array(get_tags(resource)).map(&:to_s).map(&:to_sym)
+
+        results.each do |k|
+          sum[k] ||= []
+          sum[k] << resource
+        end
+      end
+
+      tags = articles
+          .select { |resource| resource.data.tags }
+          .each_with_object({}, &method(:group_lookup))
+
+      tags.each do |k, articles_in_tag|
+        articles_in_tag.sort { |a, b|
+          b.data.date <=> a.data.date
+        }.per_page(2).each do |items, num, meta, is_last|
+          page_path = num == 1 ? "/tags/#{k}.html" : "/tags/#{k}/page/#{num}.html"
+
+          prev_page = case num
+          when 1
+            nil
+          when 2
+            "/tags/#{k}.html"
+          when 3
+            "/tags/#{k}/page/#{num-1}.html"
+          end
+
+          next_page = is_last ? nil : "/tags/#{k}/page/#{num+1}.html"
+
+          proxy page_path, "/archive/2011/index.html", locals: {
+            items: items,
+            pagination: meta,
+            prev_page: prev_page,
+            next_page: next_page
+          }
+        end
+      end
+      """
+    And the Server is running
+    When I go to "/2011/index.html"
+    Then I should see "Paginate: true"
+    Then I should see "Article Count: 5"
+    Then I should see "Page Num: 1"
+    Then I should see "Num Pages: 2"
+    Then I should see "Per Page: 5"
+    Then I should see "Page Start: 1"
+    Then I should see "Page End: 5"
+    Then I should see "Next Page: '/2011/page/2.html'"
+    Then I should see "Prev Page: ''"
+    Then I should not see "/blog/2011-01-01-test-article.html"
+    Then I should not see "/blog/2011-01-02-test-article.html"
+    Then I should see "/blog/2011-01-03-test-article.html"
+    Then I should see "/blog/2011-01-04-test-article.html"
+    Then I should see "/blog/2011-01-05-test-article.html"
+    Then I should see "/blog/2011-02-01-test-article.html"
+    Then I should see "/blog/2011-02-02-test-article.html"
+
+    When I go to "/2011/page/2.html"
+    Then I should see "Article Count: 2"
+    Then I should see "Page Num: 2"
+    Then I should see "Page Start: 6"
+    Then I should see "Page End: 7"
+    Then I should see "Next Page: ''"
+    Then I should see "Prev Page: '/2011/'"
+    Then I should see "/2011-01-01-test-article.html"
+    Then I should see "/2011-01-02-test-article.html"
+    Then I should not see "/2011-01-03-test-article.html"
+    Then I should not see "/2011-01-04-test-article.html"
+    Then I should not see "/2011-01-05-test-article.html"
+    Then I should not see "/2011-02-01-test-article.html"
+    Then I should not see "/2011-02-02-test-article.html"
+
+    When I go to "/tags/bar.html"
+    Then I should see "Paginate: true"
+    Then I should see "Article Count: 2"
+    Then I should see "Page Num: 1"
+    Then I should see "Num Pages: 3"
+    Then I should see "Per Page: 2"
+    Then I should see "Page Start: 1"
+    Then I should see "Page End: 2"
+    Then I should see "Next Page: '/tags/bar/page/2.html'"
+    Then I should see "Prev Page: ''"
+    Then I should see "/2011-02-02-test-article.html"
+    Then I should see "/2011-02-01-test-article.html"
+    Then I should not see "/2011-02-05-test-article.html"
+    Then I should not see "/2011-01-04-test-article.html"
+    Then I should not see "/2011-01-03-test-article.html"
+
+  Scenario: Custom pager method
+    Given a fixture app "paginate-app"
+    And a file named "config.rb" with:
+      """
+      def items_per_page(all_items)
+        [
+          all_items.shift(2),
+          all_items
+        ]
+      end
+
+      articles = resources.select { |r|
+        matcher = ::Middleman::Util::UriTemplates.uri_template('blog/2011-{remaining}')
+        ::Middleman::Util::UriTemplates.extract_params(matcher, ::Middleman::Util.normalize_path(r.url))
+      }
+
+      articles.sort { |a, b|
+        b.data.date <=> a.data.date
+      }.per_page(method(:items_per_page).to_proc).each do |items, num, meta, is_last|
+        page_path = num == 1 ? '/2011/index.html' : "/2011/page/#{num}.html"
+
+        prev_page = case num
+        when 1
+          nil
+        when 2
+          '/2011/index.html'
+        when 3
+          "/2011/page/#{num-1}.html"
+        end
+
+        next_page = is_last ? nil : "/2011/page/#{num+1}.html"
+
+        proxy page_path, "/archive/2011/index.html", locals: {
+          items: items,
+          pagination: meta,
+          prev_page: prev_page,
+          next_page: next_page
+        }
+      end
+      """
+    And the Server is running
+    When I go to "/2011/index.html"
+    Then I should see "Paginate: true"
+    Then I should see "Article Count: 2"
+    Then I should see "Page Num: 1"
+    Then I should see "Num Pages: 2"
+    Then I should see "Per Page: 2"
+    Then I should see "Page Start: 1"
+    Then I should see "Page End: 2"
+    Then I should see "Next Page: '/2011/page/2.html'"
+    Then I should see "Prev Page: ''"
+    Then I should not see "/blog/2011-01-01-test-article.html"
+    Then I should not see "/blog/2011-01-02-test-article.html"
+    Then I should not see "/blog/2011-01-03-test-article.html"
+    Then I should not see "/blog/2011-01-04-test-article.html"
+    Then I should not see "/blog/2011-01-05-test-article.html"
+    Then I should see "/blog/2011-02-01-test-article.html"
+    Then I should see "/blog/2011-02-02-test-article.html"
+
+    When I go to "/2011/page/2.html"
+    Then I should see "Article Count: 5"
+    Then I should see "Page Num: 2"
+    Then I should see "Page Start: 3"
+    Then I should see "Page End: 7"
+    Then I should see "Next Page: ''"
+    Then I should see "Prev Page: '/2011/'"
+    Then I should see "/2011-01-01-test-article.html"
+    Then I should see "/2011-01-02-test-article.html"
+    Then I should see "/2011-01-03-test-article.html"
+    Then I should see "/2011-01-04-test-article.html"
+    Then I should see "/2011-01-05-test-article.html"
+    Then I should not see "/2011-02-01-test-article.html"
+    Then I should not see "/2011-02-02-test-article.html"
diff --git a/middleman-core/fixtures/collections-app/config.rb b/middleman-core/fixtures/collections-app/config.rb
new file mode 100644
index 00000000..ae9cb817
--- /dev/null
+++ b/middleman-core/fixtures/collections-app/config.rb
@@ -0,0 +1,16 @@
+collection :articles,
+  where: proc { |resource|
+    uri_match resource.url, 'blog/{year}-{month}-{day}-{title}.html'
+  }
+
+collection :tags,
+  where: proc { |resource|
+    resource.data.tags
+  },
+  group_by: proc { |resource|
+    if resource.data.tags.is_a? String
+      resource.data.tags.split(',').map(&:strip)
+    else
+      resource.data.tags
+    end
+  }
\ No newline at end of file
diff --git a/middleman-core/fixtures/collections-app/source/blog1/2011-01-01-new-article.html.markdown b/middleman-core/fixtures/collections-app/source/blog1/2011-01-01-new-article.html.markdown
new file mode 100755
index 00000000..a96bcc00
--- /dev/null
+++ b/middleman-core/fixtures/collections-app/source/blog1/2011-01-01-new-article.html.markdown
@@ -0,0 +1,7 @@
+--- 
+title: "Blog1 Newer Article"
+date: 2011-01-01
+tags: foo, bar
+---
+
+Newer Article Content
diff --git a/middleman-core/fixtures/collections-app/source/blog1/2011-01-02-another-article.html.markdown b/middleman-core/fixtures/collections-app/source/blog1/2011-01-02-another-article.html.markdown
new file mode 100755
index 00000000..feb086af
--- /dev/null
+++ b/middleman-core/fixtures/collections-app/source/blog1/2011-01-02-another-article.html.markdown
@@ -0,0 +1,9 @@
+---
+title: "Blog1 Another Article"
+date: 2011-01-02
+tags:
+  - foo
+  - 120
+---
+
+Another Article Content
diff --git a/middleman-core/fixtures/collections-app/source/blog2/2011-01-01-new-article.html.markdown b/middleman-core/fixtures/collections-app/source/blog2/2011-01-01-new-article.html.markdown
new file mode 100755
index 00000000..125b71fa
--- /dev/null
+++ b/middleman-core/fixtures/collections-app/source/blog2/2011-01-01-new-article.html.markdown
@@ -0,0 +1,7 @@
+--- 
+title: "Blog2 Newer Article"
+date: 2011-01-01
+tags: foo, bar
+---
+
+Newer Article Content
diff --git a/middleman-core/fixtures/collections-app/source/blog2/2011-01-02-another-article.html.markdown b/middleman-core/fixtures/collections-app/source/blog2/2011-01-02-another-article.html.markdown
new file mode 100755
index 00000000..18656883
--- /dev/null
+++ b/middleman-core/fixtures/collections-app/source/blog2/2011-01-02-another-article.html.markdown
@@ -0,0 +1,8 @@
+---
+title: "Blog2 Another Article"
+date: 2011-01-02
+tags:
+  - foo
+---
+
+Another Article Content
diff --git a/middleman-core/fixtures/collections-app/source/index.html.erb b/middleman-core/fixtures/collections-app/source/index.html.erb
new file mode 100644
index 00000000..0d6f2ad5
--- /dev/null
+++ b/middleman-core/fixtures/collections-app/source/index.html.erb
@@ -0,0 +1,26 @@
+<!doctype html>
+<html>
+  <head>
+  </head>
+  <body>
+
+<!-- ARTICLES -->
+<% collected.articles.each do |article| %>
+  <li>
+    <a href="<%= article.url %>">Article: <%= article.data.title %></a>
+    <time><%= article.data.date.strftime('%b %e') %></time>
+  </li>
+<% end %>
+
+<!-- TAGS -->
+<% collected[:tags].each do |k, items| %>
+  <li>
+    <%= k %>
+    <% items.each do |article| %>
+      <%= article.data.title %>
+    <% end %>
+  </li>
+<% end %>
+
+  </body>
+</html>
diff --git a/middleman-core/fixtures/paginate-app/config.rb b/middleman-core/fixtures/paginate-app/config.rb
new file mode 100644
index 00000000..e69de29b
diff --git a/middleman-core/fixtures/paginate-app/source/archive/2011/index.html.erb b/middleman-core/fixtures/paginate-app/source/archive/2011/index.html.erb
new file mode 100644
index 00000000..952be1ad
--- /dev/null
+++ b/middleman-core/fixtures/paginate-app/source/archive/2011/index.html.erb
@@ -0,0 +1,20 @@
+Year: '<%#= year %>'
+
+Paginate: <%= !!pagination %>
+Article Count: <%= items.length %>
+<% if pagination %>
+Page Num: <%= pagination.page_number %>
+Num Pages: <%= pagination.num_pages %>
+Per Page: <%= pagination.per_page %>
+Page Start: <%= pagination.page_start %>
+Page End: <%= pagination.page_end %>
+Next Page: '<%= sitemap.find_resource_by_destination_path(next_page).url if next_page %>'
+Prev Page: '<%= sitemap.find_resource_by_destination_path(prev_page).url if prev_page %>'
+<% end %>
+
+<% items.each do |article| %>
+  <article>
+    <%= article.data.title %>
+    <%= article.url %>
+  </article>
+<% end %>
diff --git a/middleman-core/fixtures/paginate-app/source/blog/2011-01-01-test-article.html.markdown b/middleman-core/fixtures/paginate-app/source/blog/2011-01-01-test-article.html.markdown
new file mode 100755
index 00000000..42301a3b
--- /dev/null
+++ b/middleman-core/fixtures/paginate-app/source/blog/2011-01-01-test-article.html.markdown
@@ -0,0 +1,6 @@
+---
+title: "Test Article"
+date: 2011-01-01
+tags: foo
+---
+Test Article Content
diff --git a/middleman-core/fixtures/paginate-app/source/blog/2011-01-02-test-article.html.markdown b/middleman-core/fixtures/paginate-app/source/blog/2011-01-02-test-article.html.markdown
new file mode 100755
index 00000000..fc31d996
--- /dev/null
+++ b/middleman-core/fixtures/paginate-app/source/blog/2011-01-02-test-article.html.markdown
@@ -0,0 +1,6 @@
+---
+title: "Test Article"
+date: 2011-01-02
+tags: foo
+---
+Test Article Content
diff --git a/middleman-core/fixtures/paginate-app/source/blog/2011-01-03-test-article.html.markdown b/middleman-core/fixtures/paginate-app/source/blog/2011-01-03-test-article.html.markdown
new file mode 100755
index 00000000..bad0a289
--- /dev/null
+++ b/middleman-core/fixtures/paginate-app/source/blog/2011-01-03-test-article.html.markdown
@@ -0,0 +1,6 @@
+---
+title: "Test Article"
+date: 2011-01-03
+tags: bar
+---
+Test Article Content
diff --git a/middleman-core/fixtures/paginate-app/source/blog/2011-01-04-test-article.html.markdown b/middleman-core/fixtures/paginate-app/source/blog/2011-01-04-test-article.html.markdown
new file mode 100755
index 00000000..25702e8e
--- /dev/null
+++ b/middleman-core/fixtures/paginate-app/source/blog/2011-01-04-test-article.html.markdown
@@ -0,0 +1,6 @@
+---
+title: "Test Article"
+date: 2011-01-04
+tags: bar
+---
+Test Article Content
diff --git a/middleman-core/fixtures/paginate-app/source/blog/2011-01-05-test-article.html.markdown b/middleman-core/fixtures/paginate-app/source/blog/2011-01-05-test-article.html.markdown
new file mode 100755
index 00000000..2efb79a0
--- /dev/null
+++ b/middleman-core/fixtures/paginate-app/source/blog/2011-01-05-test-article.html.markdown
@@ -0,0 +1,6 @@
+---
+title: "Test Article"
+date: 2011-01-05
+tags: bar
+---
+Test Article Content
diff --git a/middleman-core/fixtures/paginate-app/source/blog/2011-02-01-test-article.html.markdown b/middleman-core/fixtures/paginate-app/source/blog/2011-02-01-test-article.html.markdown
new file mode 100755
index 00000000..cd8e2201
--- /dev/null
+++ b/middleman-core/fixtures/paginate-app/source/blog/2011-02-01-test-article.html.markdown
@@ -0,0 +1,6 @@
+---
+title: "Test Article"
+date: 2011-02-01
+tags: bar
+---
+Test Article Content
diff --git a/middleman-core/fixtures/paginate-app/source/blog/2011-02-02-test-article.html.markdown b/middleman-core/fixtures/paginate-app/source/blog/2011-02-02-test-article.html.markdown
new file mode 100755
index 00000000..701c25c7
--- /dev/null
+++ b/middleman-core/fixtures/paginate-app/source/blog/2011-02-02-test-article.html.markdown
@@ -0,0 +1,6 @@
+---
+title: "Test Article"
+date: 2011-02-02
+tags: bar
+---
+Test Article Content
diff --git a/middleman-core/fixtures/paginate-app/source/index.html.erb b/middleman-core/fixtures/paginate-app/source/index.html.erb
new file mode 100644
index 00000000..976fc5d9
--- /dev/null
+++ b/middleman-core/fixtures/paginate-app/source/index.html.erb
@@ -0,0 +1,15 @@
+Paginate: <%= paginate %>
+Article Count: <%= page_articles.size %>
+<% if paginate %>
+Page Num: <%= page_number %>
+Num Pages: <%= num_pages %>
+Per Page: <%= per_page %>
+Page Start: <%= page_start %>
+Page End: <%= page_end %>
+Next Page: '<%= next_page.url if next_page %>'
+Prev Page: '<%= prev_page.url if prev_page %>'
+<% end %>
+
+<% page_articles.each do |article| %>
+  <li><a href="<%= article.url %>"><%= article.title %></a> <time><%= article.date.strftime('%b %e') %></time></li>
+<% end %>
diff --git a/middleman-core/fixtures/paginate-app/source/tag.html.erb b/middleman-core/fixtures/paginate-app/source/tag.html.erb
new file mode 100644
index 00000000..f098d947
--- /dev/null
+++ b/middleman-core/fixtures/paginate-app/source/tag.html.erb
@@ -0,0 +1,23 @@
+---
+pageable: true
+per_page: 2
+---
+Tag: <%= tagname %>
+
+Paginate: <%= paginate %>
+Article Count: <%= page_articles.size %>
+<% if paginate %>
+Page Num: <%= page_number %>
+Num Pages: <%= num_pages %>
+Per Page: <%= per_page %>
+Page Start: <%= page_start %>
+Page End: <%= page_end %>
+Next Page: '<%= next_page.url if next_page %>'
+Prev Page: '<%= prev_page.url if prev_page %>'
+<% end %>
+
+<% if page_articles %>
+  <% page_articles.each do |article| %>
+    <li><a href="<%= article.url %>"><%= article.title %></a> <time><%= article.date.strftime('%b %e') %></time></li>
+  <% end %>
+<% end %>
diff --git a/middleman-core/lib/middleman-core/contracts.rb b/middleman-core/lib/middleman-core/contracts.rb
index ed3fcf97..9d7e77ee 100644
--- a/middleman-core/lib/middleman-core/contracts.rb
+++ b/middleman-core/lib/middleman-core/contracts.rb
@@ -59,6 +59,21 @@ if ENV['TEST'] || ENV['CONTRACTS'] == 'true'
       end
     end
 
+    # class MethodDefined
+    #   def self.[](val)
+    #     @lookup ||= {}
+    #     @lookup[val] ||= new(val)
+    #   end
+
+    #   def initialize(val)
+    #     @val = val
+    #   end
+
+    #   def valid?(val)
+    #     val.method_defined? @val
+    #   end
+    # end
+
     ResourceList = Contracts::ArrayOf[IsA['Middleman::Sitemap::Resource']]
   end
 else
@@ -141,6 +156,9 @@ else
 
     class Frozen < Callable
     end
+
+    # class MethodDefined < Callable
+    # end
   end
 end
 
diff --git a/middleman-core/lib/middleman-core/core_extensions.rb b/middleman-core/lib/middleman-core/core_extensions.rb
index 5f246d36..ea31f89a 100644
--- a/middleman-core/lib/middleman-core/core_extensions.rb
+++ b/middleman-core/lib/middleman-core/core_extensions.rb
@@ -52,6 +52,11 @@ Middleman::Extensions.register :routing, auto_activate: :before_configuration do
   Middleman::CoreExtensions::Routing
 end
 
+Middleman::Extensions.register :collections, auto_activate: :before_configuration do
+  require 'middleman-core/core_extensions/collections'
+  Middleman::CoreExtensions::Collections::CollectionsExtension
+end
+
 ###
 # Setup Optional Extensions
 ###
diff --git a/middleman-core/lib/middleman-core/core_extensions/collections.rb b/middleman-core/lib/middleman-core/core_extensions/collections.rb
new file mode 100644
index 00000000..714e1f51
--- /dev/null
+++ b/middleman-core/lib/middleman-core/core_extensions/collections.rb
@@ -0,0 +1,82 @@
+require 'middleman-core/core_extensions/collections/pagination'
+require 'middleman-core/core_extensions/collections/step_context'
+require 'middleman-core/core_extensions/collections/lazy_root'
+require 'middleman-core/core_extensions/collections/lazy_step'
+
+# Super "class-y" injection of array helpers
+class Array
+  include Middleman::Pagination::ArrayHelpers
+end
+
+module Middleman
+  module CoreExtensions
+    module Collections
+      class CollectionsExtension < Extension
+        # This should run after most other sitemap manipulators so that it
+        # gets a chance to modify any new resources that get added.
+        self.resource_list_manipulator_priority = 110
+
+        attr_accessor :root_collector, :leaves
+
+        def initialize(app, options_hash={}, &block)
+          super
+
+          @leaves = Set.new
+          @collectors_by_name = {}
+          @values_by_name = {}
+
+          @root_collector = LazyCollectorRoot.new(self)
+        end
+
+        Contract None => Any
+        def before_configuration
+          @leaves.clear
+
+          app.add_to_config_context :resources, &method(:root_collector)
+          app.add_to_config_context :collection, &method(:register_collector)
+        end
+
+        Contract Symbol, LazyCollectorStep => Any
+        def register_collector(label, endpoint)
+          @collectors_by_name[label] = endpoint
+        end
+
+        Contract Symbol => Any
+        def collector_value(label)
+          @values_by_name[label]
+        end
+
+        Contract ResourceList => ResourceList
+        def manipulate_resource_list(resources)
+          @root_collector.realize!(resources)
+
+          ctx = StepContext.new
+          leaves = @leaves.dup
+
+          @collectors_by_name.each do |k, v|
+            @values_by_name[k] = v.value(ctx)
+            leaves.delete v
+          end
+
+          # Execute code paths
+          leaves.each do |v|
+            v.value(ctx)
+          end
+
+          # Inject descriptors
+          resources + ctx.descriptors.map { |d| d.to_resource(app) }
+        end
+
+        helpers do
+          def collection(label)
+            extensions[:collections].collector_value(label)
+          end
+
+          def pagination
+            current_resource.data.pagination
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/middleman-core/lib/middleman-core/core_extensions/collections/lazy_root.rb b/middleman-core/lib/middleman-core/core_extensions/collections/lazy_root.rb
new file mode 100644
index 00000000..6922e64a
--- /dev/null
+++ b/middleman-core/lib/middleman-core/core_extensions/collections/lazy_root.rb
@@ -0,0 +1,30 @@
+require 'middleman-core/core_extensions/collections/lazy_step'
+
+module Middleman
+  module CoreExtensions
+    module Collections
+      class LazyCollectorRoot < BasicObject
+        def initialize(parent)
+          @data = nil
+          @parent = parent
+        end
+
+        def realize!(data)
+          @data = data
+        end
+
+        def value(_ctx=nil)
+          @data
+        end
+
+        def leaves
+          @parent.leaves
+        end
+
+        def method_missing(name, *args, &block)
+          LazyCollectorStep.new(name, args, block, self)
+        end
+      end
+    end
+  end
+end
diff --git a/middleman-core/lib/middleman-core/core_extensions/collections/lazy_step.rb b/middleman-core/lib/middleman-core/core_extensions/collections/lazy_step.rb
new file mode 100644
index 00000000..1286af2c
--- /dev/null
+++ b/middleman-core/lib/middleman-core/core_extensions/collections/lazy_step.rb
@@ -0,0 +1,48 @@
+module Middleman
+  module CoreExtensions
+    module Collections
+      class LazyCollectorStep < BasicObject
+        DELEGATE = [:hash, :eql?]
+
+        def initialize(name, args, block, parent=nil)
+          @name = name
+          @args = args
+          @block = block
+
+          @parent = parent
+          @result = nil
+
+          leaves << self
+        end
+
+        def leaves
+          @parent.leaves
+        end
+
+        def value(ctx=nil)
+          data = @parent.value(ctx)
+
+          original_block = @block
+
+          b = if ctx
+            ::Proc.new do |*args|
+              ctx.instance_exec(*args, &original_block)
+            end
+          else
+            original_block
+          end if original_block
+
+          data.send(@name, *@args.deep_dup, &b)
+        end
+
+        def method_missing(name, *args, &block)
+          return ::Kernel.send(name, *args, &block) if DELEGATE.include? name
+
+          leaves.delete self
+
+          LazyCollectorStep.new(name, args, block, self)
+        end
+      end
+    end
+  end
+end
diff --git a/middleman-core/lib/middleman-core/core_extensions/collections/pagination.rb b/middleman-core/lib/middleman-core/core_extensions/collections/pagination.rb
new file mode 100644
index 00000000..24ae8181
--- /dev/null
+++ b/middleman-core/lib/middleman-core/core_extensions/collections/pagination.rb
@@ -0,0 +1,59 @@
+require 'active_support/core_ext/object/deep_dup'
+require 'middleman-core/util'
+
+module Middleman
+  module Pagination
+    module ArrayHelpers
+      def per_page(per_page)
+        return enum_for(:per_page, per_page) unless block_given?
+
+        parts = if per_page.respond_to? :call
+          per_page.call(dup)
+        else
+          each_slice(per_page).reduce([]) do |sum, items|
+            sum << items
+          end
+        end
+
+        num_pages = parts.length
+        collection = self
+
+        current_start_i = 0
+        parts.each_with_index do |items, i|
+          num = i + 1
+
+          meta = ::Middleman::Pagination.page_locals(
+            num,
+            num_pages,
+            collection,
+            items,
+            current_start_i
+          )
+
+          yield items, num, meta, num >= num_pages
+
+          current_start_i += items.length
+        end
+      end
+    end
+
+    def self.page_locals(page_num, num_pages, collection, items, page_start)
+      per_page = items.length
+
+      # Index into collection of the last item of this page
+      page_end = (page_start + per_page) - 1
+
+      ::Middleman::Util.recursively_enhance(page_number: page_num,
+                                            num_pages: num_pages,
+                                            per_page: per_page,
+
+                                            # The range of item numbers on this page
+                                            # (1-based, for showing "Items X to Y of Z")
+                                            page_start: page_start + 1,
+                                            page_end: [page_end + 1, collection.length].min,
+
+                                            # Use "collection" in templates.
+                                            collection: collection)
+    end
+  end
+end
diff --git a/middleman-core/lib/middleman-core/core_extensions/collections/step_context.rb b/middleman-core/lib/middleman-core/core_extensions/collections/step_context.rb
new file mode 100644
index 00000000..740b8188
--- /dev/null
+++ b/middleman-core/lib/middleman-core/core_extensions/collections/step_context.rb
@@ -0,0 +1,26 @@
+module Middleman
+  module CoreExtensions
+    module Collections
+      class StepContext
+        def self.add_to_context(name, &func)
+          send(:define_method, :"_internal_#{name}", &func)
+        end
+
+        attr_reader :descriptors
+
+        def initialize
+          @descriptors = []
+        end
+
+        def method_missing(name, *args, &block)
+          internal = :"_internal_#{name}"
+          if respond_to?(internal)
+            @descriptors << send(internal, *args, &block)
+          else
+            super
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/middleman-core/lib/middleman-core/core_extensions/show_exceptions.rb b/middleman-core/lib/middleman-core/core_extensions/show_exceptions.rb
index ba9fdade..7d38812f 100644
--- a/middleman-core/lib/middleman-core/core_extensions/show_exceptions.rb
+++ b/middleman-core/lib/middleman-core/core_extensions/show_exceptions.rb
@@ -12,7 +12,7 @@ module Middleman::CoreExtensions
     end
 
     def after_configuration
-      app.use ::Rack::ShowExceptions if app.config[:show_exceptions]
+      app.use ::Rack::ShowExceptions if !app.build? && app.config[:show_exceptions]
     end
   end
 end
diff --git a/middleman-core/lib/middleman-core/sitemap/extensions/proxies.rb b/middleman-core/lib/middleman-core/sitemap/extensions/proxies.rb
index 95f30c52..90bff4fc 100644
--- a/middleman-core/lib/middleman-core/sitemap/extensions/proxies.rb
+++ b/middleman-core/lib/middleman-core/sitemap/extensions/proxies.rb
@@ -1,4 +1,5 @@
 require 'middleman-core/sitemap/resource'
+require 'middleman-core/core_extensions/collections/step_context'
 
 module Middleman
   module Sitemap
@@ -13,6 +14,13 @@ module Middleman
           @app.define_singleton_method(:proxy, &method(:create_proxy))
 
           @proxy_configs = Set.new
+          @post_config = false
+        end
+
+        def after_configuration
+          @post_config = true
+
+          ::Middleman::CoreExtensions::Collections::StepContext.add_to_context(:proxy, &method(:create_anonymous_proxy))
         end
 
         # Setup a proxy from a path to a target
@@ -27,70 +35,48 @@ module Middleman
         Contract String, String, Maybe[Hash] => Any
         def create_proxy(path, target, opts={})
           options = opts.dup
-
           @app.ignore(target) if options.delete(:ignore)
 
-          metadata = {
-            options: options,
-            locals: options.delete(:locals) || {},
-            page: options.delete(:data) || {}
-          }
-
-          @proxy_configs << ProxyConfiguration.new(path: path, target: target, metadata: metadata)
-
+          @proxy_configs << create_anonymous_proxy(path, target, options)
           @app.sitemap.rebuild_resource_list!(:added_proxy)
         end
 
+        # Setup a proxy from a path to a target
+        # @param [String] path The new, proxied path to create
+        # @param [String] target The existing path that should be proxied to. This must be a real resource, not another proxy.
+        # @option opts [Boolean] ignore Ignore the target from the sitemap (so only the new, proxy resource ends up in the output)
+        # @option opts [Symbol, Boolean, String] layout The layout name to use (e.g. `:article`) or `false` to disable layout.
+        # @option opts [Boolean] directory_indexes Whether or not the `:directory_indexes` extension applies to these paths.
+        # @option opts [Hash] locals Local variables for the template. These will be available when the template renders.
+        # @option opts [Hash] data Extra metadata to add to the page. This is the same as frontmatter, though frontmatter will take precedence over metadata defined here. Available via {Resource#data}.
+        # @return [void]
+        def create_anonymous_proxy(path, target, options={})
+          ProxyDescriptor.new(
+            ::Middleman::Util.normalize_path(path),
+            ::Middleman::Util.normalize_path(target),
+            options
+          )
+        end
+
         # Update the main sitemap resource list
         # @return Array<Middleman::Sitemap::Resource>
         Contract ResourceList => ResourceList
         def manipulate_resource_list(resources)
-          resources + @proxy_configs.map do |config|
-            p = ProxyResource.new(
-              @app.sitemap,
-              config.path,
-              config.target
-            )
-
-            p.add_metadata(config.metadata)
-            p
-          end
+          resources + @proxy_configs.map { |c| c.to_resource(@app) }
         end
       end
 
-      # Configuration for a proxy instance
-      class ProxyConfiguration
-        # The path that this proxy will appear at in the sitemap
-        attr_reader :path
-        def path=(p)
-          @path = ::Middleman::Util.normalize_path(p)
-        end
-
-        # The existing sitemap path that this will proxy to
-        attr_reader :target
-        def target=(t)
-          @target = ::Middleman::Util.normalize_path(t)
-        end
-
-        # Additional metadata like locals to apply to the proxy
-        attr_accessor :metadata
-
-        # Create a new proxy configuration from hash options
-        def initialize(options={})
-          options.each do |key, value|
-            send "#{key}=", value
+      ProxyDescriptor = Struct.new(:path, :target, :metadata) do
+        def to_resource(app)
+          ProxyResource.new(app.sitemap, path, target).tap do |p|
+            md = metadata.dup
+            p.add_metadata(
+                             locals: md.delete(:locals) || {},
+                             page: md.delete(:data) || {},
+                             options: md
+                           )
           end
         end
-
-        # Two configurations are equal if they reference the same path
-        def eql?(other)
-          other.path == path
-        end
-
-        # Two configurations are equal if they reference the same path
-        def hash
-          path.hash
-        end
       end
     end
 
diff --git a/middleman-core/lib/middleman-core/sitemap/resource.rb b/middleman-core/lib/middleman-core/sitemap/resource.rb
index ae2ffa73..f7ae229c 100644
--- a/middleman-core/lib/middleman-core/sitemap/resource.rb
+++ b/middleman-core/lib/middleman-core/sitemap/resource.rb
@@ -165,7 +165,11 @@ module Middleman
         # Ignore based on the source path (without template extensions)
         return true if @app.sitemap.ignored?(path)
         # This allows files to be ignored by their source file name (with template extensions)
-        !self.is_a?(ProxyResource) && @app.sitemap.ignored?(source_file[:relative_path].to_s)
+        if !self.is_a?(ProxyResource) && source_file && @app.sitemap.ignored?(source_file[:relative_path].to_s)
+          true
+        else
+          false
+        end
       end
 
       # The preferred MIME content type for this resource based on extension or metadata
@@ -174,6 +178,31 @@ module Middleman
       def content_type
         options[:content_type] || ::Rack::Mime.mime_type(ext, nil)
       end
+
+      def to_s
+        "#<Middleman::Sitemap::Resource path=#{@path}>"
+      end
+      alias_method :inspect, :to_s # Ruby 2.0 calls inspect for NoMethodError instead of to_s
+    end
+
+    class StringResource < Resource
+      def initialize(store, path, contents=nil, &block)
+        @request_path = path
+        @contents = block_given? ? block : contents
+        super(store, path)
+      end
+
+      def template?
+        true
+      end
+
+      def render(*)
+        @contents.respond_to?(:call) ? @contents.call : @contents
+      end
+
+      def binary?
+        false
+      end
     end
   end
 end
diff --git a/middleman-core/lib/middleman-core/sitemap/store.rb b/middleman-core/lib/middleman-core/sitemap/store.rb
index 82084c14..067f3f33 100644
--- a/middleman-core/lib/middleman-core/sitemap/store.rb
+++ b/middleman-core/lib/middleman-core/sitemap/store.rb
@@ -49,11 +49,15 @@ module Middleman
       # @return [Middleman::Application]
       attr_reader :app
 
+      attr_reader :update_count
+
       # Initialize with parent app
       # @param [Middleman::Application] app
       def initialize(app)
         @app = app
         @resources = []
+        @update_count = 0
+
         # TODO: Should this be a set or hash?
         @resource_list_manipulators = []
         @needs_sitemap_rebuild = true
@@ -187,6 +191,7 @@ module Middleman
           end
 
           invalidate_resources_not_ignored_cache!
+          @update_count += 1
         end
       end
 
diff --git a/middleman-core/lib/middleman-core/sources.rb b/middleman-core/lib/middleman-core/sources.rb
index cd3eab17..2026c32b 100644
--- a/middleman-core/lib/middleman-core/sources.rb
+++ b/middleman-core/lib/middleman-core/sources.rb
@@ -172,7 +172,7 @@ module Middleman
           .lazy
           .select { |d| d.type == type }
           .map { |d| d.find(path, glob) }
-          .reject { |d| d.nil? }
+          .reject(&:nil?)
           .first
     end
 
diff --git a/middleman-core/lib/middleman-core/template_context.rb b/middleman-core/lib/middleman-core/template_context.rb
index 3021b41e..9deeccb4 100644
--- a/middleman-core/lib/middleman-core/template_context.rb
+++ b/middleman-core/lib/middleman-core/template_context.rb
@@ -102,7 +102,7 @@ module Middleman
 
       partial_file = locate_partial(name)
 
-      return "" unless partial_file
+      return '' unless partial_file
       raise ::Middleman::TemplateRenderer::TemplateNotFound, "Could not locate partial: #{name}" unless partial_file
 
       source_path = sitemap.file_to_path(partial_file)
diff --git a/middleman-core/lib/middleman-core/util.rb b/middleman-core/lib/middleman-core/util.rb
index 53a183ee..7218e281 100644
--- a/middleman-core/lib/middleman-core/util.rb
+++ b/middleman-core/lib/middleman-core/util.rb
@@ -14,6 +14,11 @@ require 'rack/mime'
 # DbC
 require 'middleman-core/contracts'
 
+# For URI templating
+require 'addressable/template'
+require 'active_support/inflector'
+require 'active_support/inflector/transliterate'
+
 module Middleman
   module Util
     include Contracts
@@ -384,5 +389,93 @@ module Middleman
         resource_url
       end
     end
+
+    # Handy methods for dealing with URI templates. Mix into whatever class.
+    module UriTemplates
+      module_function
+
+      # Given a URI template string, make an Addressable::Template
+      # This supports the legacy middleman-blog/Sinatra style :colon
+      # URI templates as well as RFC6570 templates.
+      #
+      # @param [String] tmpl_src URI template source
+      # @return [Addressable::Template] a URI template
+      def uri_template(tmpl_src)
+        # Support the RFC6470 templates directly if people use them
+        if tmpl_src.include?(':')
+          tmpl_src = tmpl_src.gsub(/:([A-Za-z0-9]+)/, '{\1}')
+        end
+
+        Addressable::Template.new ::Middleman::Util.normalize_path(tmpl_src)
+      end
+
+      # Apply a URI template with the given data, producing a normalized
+      # Middleman path.
+      #
+      # @param [Addressable::Template] template
+      # @param [Hash] data
+      # @return [String] normalized path
+      def apply_uri_template(template, data)
+        ::Middleman::Util.normalize_path Addressable::URI.unencode(template.expand(data)).to_s
+      end
+
+      # Use a template to extract parameters from a path, and validate some special (date)
+      # keys. Returns nil if the special keys don't match.
+      #
+      # @param [Addressable::Template] template
+      # @param [String] path
+      def extract_params(template, path)
+        template.extract(path, BlogTemplateProcessor)
+      end
+
+      # Parameterize a string preserving any multibyte characters
+      def safe_parameterize(str)
+        sep = '-'
+
+        # Reimplementation of http://api.rubyonrails.org/classes/ActiveSupport/Inflector.html#method-i-parameterize that preserves un-transliterate-able multibyte chars.
+        parameterized_string = ActiveSupport::Inflector.transliterate(str.to_s).downcase
+        parameterized_string.gsub!(/[^a-z0-9\-_\?]+/, sep)
+
+        parameterized_string.chars.to_a.each_with_index do |char, i|
+          next unless char == '?' && str[i].bytes.count != 1
+          parameterized_string[i] = str[i]
+        end
+
+        re_sep = Regexp.escape(sep)
+        # No more than one of the separator in a row.
+        parameterized_string.gsub!(/#{re_sep}{2,}/, sep)
+        # Remove leading/trailing separator.
+        parameterized_string.gsub!(/^#{re_sep}|#{re_sep}$/, '')
+
+        parameterized_string
+      end
+
+      # Convert a date into a hash of components to strings
+      # suitable for using in a URL template.
+      # @param [DateTime] date
+      # @return [Hash] parameters
+      def date_to_params(date)
+        {
+          year: date.year.to_s,
+          month: date.month.to_s.rjust(2, '0'),
+          day: date.day.to_s.rjust(2, '0')
+        }
+      end
+    end
+
+    # A special template processor that validates date fields
+    # and has an extra-permissive default regex.
+    #
+    # See https://github.com/sporkmonger/addressable/blob/master/lib/addressable/template.rb#L279
+    class BlogTemplateProcessor
+      def self.match(name)
+        case name
+        when 'year' then '\d{4}'
+        when 'month' then '\d{2}'
+        when 'day' then '\d{2}'
+        else '.*?'
+        end
+      end
+    end
   end
 end
diff --git a/middleman-core/middleman-core.gemspec b/middleman-core/middleman-core.gemspec
index 397928dc..b3c3782d 100644
--- a/middleman-core/middleman-core.gemspec
+++ b/middleman-core/middleman-core.gemspec
@@ -29,6 +29,7 @@ Gem::Specification.new do |s|
   # Helpers
   s.add_dependency('activesupport', ['~> 4.1.0'])
   s.add_dependency('padrino-helpers', ['~> 0.12.3'])
+  s.add_dependency("addressable", ["~> 2.3.5"])
 
   # Watcher
   s.add_dependency('listen', ['>= 2.7.9', '< 3.0'])