diff --git a/CHANGES b/CHANGES
index 0c6fd81043..55461bc33f 100644
--- a/CHANGES
+++ b/CHANGES
@@ -11,14 +11,23 @@
  * Important: 1.8.6 support has been dropped. It is still usable if you use the
    backports gem, but no longer officially supported. (Konstantin Haase)
 
- * It is now possible to use a different target class for the top level DLS (aka
+ * It is now possible to use a different target class for the top level DSL (aka
    classic style) than `Sinatra::Application` by setting `Delegator.target`.
    This was mainly introduced to ease testing. (Konstantin Haase)
 
  * Added `request.accept?` and `request.preferred_type` to ease dealing with
    `Accept` headers. (Konstantin Haase)
 
-= 1.2.2 / Not Yet Released
+= 1.2.3 / 2011-04-13
+
+ * This release is compatible with Tilt 1.3, it will still work with Tilt 1.2.2,
+   however, if you want to use a newer Tilt version, you have to upgrade to at
+   least this version of Sinatra. (Konstantin Haase)
+
+ * Helpers dealing with time, like `expires`, handle objects that pretend to be
+   numbers, like `ActiveSupport::Duration`, better. (Konstantin Haase)
+
+= 1.2.2 / 2011-04-08
 
  * The `:provides => :js` condition now matches both `application/javascript`
    and `text/javascript`. The `:provides => :xml` condition now matches both
@@ -108,6 +117,10 @@
  * Sinatra now ships with a Gemfile for development dependencies, since it eases
    supporting different platforms, like JRuby. (Konstantin Haase)
 
+= 1.1.4 / 2011-04-13
+
+ * Compatible with Tilt 1.3. (Konstantin Haase)
+
 = 1.1.3 / 2011-02-20
 
  * Fixed issues with `user_agent` condition if the user agent header is missing.
diff --git a/Gemfile b/Gemfile
index 8e67ef0b1f..46929454ce 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,6 +7,7 @@
 # If you have issues with a gem: `bundle install --without-coffee-script`.
 
 RUBY_ENGINE = 'ruby' unless defined? RUBY_ENGINE
+TILT_REPO = "git://github.com/rtomayko/tilt.git"
 
 source :rubygems unless ENV['QUICK']
 gemspec
@@ -14,6 +15,15 @@ gemspec
 gem 'rake'
 gem 'rack-test', '>= 0.5.6'
 
+# Allows stuff like `tilt=1.2.2 bundle install` or `tilt=master ...`.
+# Used by the CI.
+tilt = ENV['tilt'].dup || 'stable'
+tilt.sub! 'tilt-', ''
+if tilt != 'stable'
+  tilt = {:git => TILT_REPO, :branch => tilt} unless tilt =~ /(\d+\.)+\d+/
+  gem 'tilt', tilt
+end
+
 gem 'haml', '>= 3.0', :group => 'haml'
 gem 'builder', :group => 'builder'
 gem 'erubis', :group => 'erubis'
@@ -39,5 +49,4 @@ platforms :mri_18 do
   # bundler platforms are broken
   next if RUBY_ENGINE != 'ruby' or RUBY_VERSION > "1.8"
   gem 'rcov', :group => 'rcov'
-  gem 'therubyracer', :group => 'coffee-script'
 end
diff --git a/README.rdoc b/README.rdoc
index 4d8dbf95a5..f29db905cd 100644
--- a/README.rdoc
+++ b/README.rdoc
@@ -1882,4 +1882,7 @@ SemVerTag.
 * {Twitter}[http://twitter.com/sinatra]
 * {Mailing List}[http://groups.google.com/group/sinatrarb/topics]
 * {IRC: #sinatra}[irc://chat.freenode.net/#sinatra] on http://freenode.net
+* API documentation for the {latest release}[http://rubydoc.info/gems/sinatra]
+  or the {current HEAD}[http://rubydoc.info/github/sinatra/sinatra] on
+  http://rubydoc.info/
 
diff --git a/lib/sinatra/base.rb b/lib/sinatra/base.rb
index 6f91d74640..3b09a1c6ef 100644
--- a/lib/sinatra/base.rb
+++ b/lib/sinatra/base.rb
@@ -340,8 +340,8 @@ def cache_control(*values)
     def expires(amount, *values)
       values << {} unless values.last.kind_of?(Hash)
 
-      if Integer === amount
-        time    = Time.now + amount
+      if amount.is_a? Integer
+        time    = Time.now + amount.to_i
         max_age = amount
       else
         time    = time_for amount
@@ -405,7 +405,7 @@ def back
     def time_for(value)
       if value.respond_to? :to_time
         value.to_time
-      elsif Time === value
+      elsif value.is_a? Time
         value
       elsif value.respond_to? :new_offset
         # DateTime#to_time does the same on 1.9
@@ -415,13 +415,13 @@ def time_for(value)
       elsif value.respond_to? :mday
         # Date#to_time does the same on 1.9
         Time.local(value.year, value.mon, value.mday)
-      elsif Numeric === value
+      elsif value.is_a? Numeric
         Time.at value
       else
         Time.parse value.to_s
       end
     rescue ArgumentError => boom
-      raise boom.to_s
+      raise boom
     rescue Exception
       raise ArgumentError, "unable to convert #{value.inspect} to a Time object"
     end
@@ -523,8 +523,9 @@ def slim(template, options={}, locals={})
     # Calls the given block for every possible template file in views,
     # named name.ext, where ext is registered on engine.
     def find_template(views, name, engine)
-      Tilt.mappings.each do |ext, klass|
-        next unless klass == engine
+      yield ::File.join(views, "#{name}.#{@preferred_extension}")
+      Tilt.mappings.each do |ext, engines|
+        next unless ext != @preferred_extension and Array(engines).include? engine
         yield ::File.join(views, "#{name}.#{ext}")
       end
     end
@@ -585,6 +586,7 @@ def compile_template(engine, data, options, views)
             template.new(path, line.to_i, options) { body }
           else
             found = false
+            @preferred_extension = engine.to_s
             find_template(views, data, template) do |file|
               path ||= file # keep the initial path rather than the last one
               if found = File.exists?(file)
diff --git a/sinatra.gemspec b/sinatra.gemspec
index c0712dd8b4..074ea357b5 100644
--- a/sinatra.gemspec
+++ b/sinatra.gemspec
@@ -123,10 +123,9 @@ Gem::Specification.new do |s|
 
   s.extra_rdoc_files = %w[README.rdoc README.de.rdoc README.jp.rdoc README.fr.rdoc README.es.rdoc README.hu.rdoc README.zh.rdoc LICENSE]
   s.add_dependency 'rack', '~> 1.2'
-  s.add_dependency 'tilt', '>= 1.2.2', '< 2.0'
+  s.add_dependency 'tilt', '~> 1.2', '>= 1.2.2'
   s.add_development_dependency 'shotgun', '~> 0.6'
 
-  s.has_rdoc = true
   s.homepage = "http://sinatra.rubyforge.org"
   s.rdoc_options = ["--line-numbers", "--inline-source", "--title", "Sinatra", "--main", "README.rdoc"]
   s.require_paths = %w[lib]
diff --git a/test/coffee_test.rb b/test/coffee_test.rb
index 918139b4ba..c8c84429b5 100644
--- a/test/coffee_test.rb
+++ b/test/coffee_test.rb
@@ -2,6 +2,13 @@
 
 begin
 require 'coffee-script'
+require 'execjs'
+
+begin
+  ExecJS.compile '1'
+rescue Exception
+  raise LoadError, 'unable to execute JavaScript'
+end
 
 class CoffeeTest < Test::Unit::TestCase
   def coffee_app(options = {}, &block)
@@ -16,7 +23,7 @@ def coffee_app(options = {}, &block)
   it 'renders inline Coffee strings' do
     coffee_app { coffee "alert 'Aye!'\n" }
     assert ok?
-    assert_equal "(function() {\n  alert('Aye!');\n}).call(this);\n", body
+    assert body.include?("alert('Aye!');")
   end
 
   it 'defaults content type to javascript' do
@@ -45,13 +52,13 @@ def coffee_app(options = {}, &block)
   it 'renders .coffee files in views path' do
     coffee_app { coffee :hello }
     assert ok?
-    assert_equal "(function() {\n  alert(\"Aye!\");\n}).call(this);\n", body
+    assert_include body, "alert(\"Aye!\");"
   end
 
   it 'ignores the layout option' do
     coffee_app { coffee :hello, :layout => :layout2 }
     assert ok?
-    assert_equal "(function() {\n  alert(\"Aye!\");\n}).call(this);\n", body
+    assert_include body, "alert(\"Aye!\");"
   end
 
   it "raises error if template not found" do
@@ -62,21 +69,18 @@ def coffee_app(options = {}, &block)
   end
 
   it "passes coffee options to the coffee engine" do
-    coffee_app {
-      coffee "alert 'Aye!'\n",
-        :no_wrap => true
-    }
+    coffee_app { coffee "alert 'Aye!'\n", :no_wrap => true }
     assert ok?
     assert_equal "alert('Aye!');", body
   end
 
   it "passes default coffee options to the coffee engine" do
-    mock_app {
+    mock_app do
       set :coffee, :no_wrap => true # default coffee style is :nested
       get '/' do
         coffee "alert 'Aye!'\n"
       end
-    }
+    end
     get '/'
     assert ok?
     assert_equal "alert('Aye!');", body
diff --git a/test/helper.rb b/test/helper.rb
index b75b03012b..99ec82454a 100644
--- a/test/helper.rb
+++ b/test/helper.rb
@@ -65,6 +65,10 @@ def assert_body(value)
     assert_equal value.lstrip.gsub(/\s*\n\s*/, ""), body.lstrip.gsub(/\s*\n\s*/, "")
   end
 
+  def assert_include(str, substr)
+    assert str.include?(substr), "expected #{str.inspect} to include #{substr.inspect}"
+  end
+
   # Delegate other missing methods to response.
   def method_missing(name, *args, &block)
     if response && response.respond_to?(name)
diff --git a/test/helpers_test.rb b/test/helpers_test.rb
index f20bf2cea8..352763e5cd 100644
--- a/test/helpers_test.rb
+++ b/test/helpers_test.rb
@@ -638,6 +638,18 @@ def send_file_app(opts={})
         get '/baz' do
           expires Time.at(0)
         end
+
+        get '/blah' do
+          obj = Object.new
+          def obj.method_missing(*a, &b) 60.send(*a, &b) end
+          def obj.is_a?(thing) 60.is_a?(thing) end
+          expires obj, :public, :no_cache
+          'Hello World'
+        end
+
+        get '/boom' do
+          expires '1000'
+        end
       end
     end
 
@@ -660,6 +672,15 @@ def send_file_app(opts={})
       get '/baz'
       assert_equal 'Thu, 01 Jan 1970 00:00:00 GMT', response['Expires']
     end
+
+    it 'accepts values pretending to be a Numeric (like ActiveSupport::Duration)' do
+      get '/blah'
+      assert_equal ['public', 'no-cache', 'max-age=60'], response['Cache-Control'].split(', ')
+    end
+
+    it 'fails when Time.parse raises an ArgumentError' do
+      assert_raise(ArgumentError) { get '/boom' }
+    end
   end
 
   describe 'last_modified' do