diff --git a/Rakefile b/Rakefile
index fb8b583..bcee060 100644
--- a/Rakefile
+++ b/Rakefile
@@ -38,7 +38,7 @@ end
 
 spec = Gem::Specification.new do |s|
   s.name        = %q{factory_girl}
-  s.version     = "1.2.2"
+  s.version     = "1.2.3"
   s.summary     = %q{factory_girl provides a framework and DSL for defining and
                      using model instance factories.}
   s.description = %q{factory_girl provides a framework and DSL for defining and
diff --git a/factory_girl.gemspec b/factory_girl.gemspec
index c3eb79d..aa0e521 100644
--- a/factory_girl.gemspec
+++ b/factory_girl.gemspec
@@ -6,19 +6,19 @@ Gem::Specification.new do |s|
 
   s.required_rubygems_version = Gem::Requirement.new(">= 0") if s.respond_to? :required_rubygems_version=
   s.authors = ["Joe Ferris"]
-  s.date = %q{2009-10-15}
+  s.date = %q{2009-10-16}
   s.description = %q{factory_girl provides a framework and DSL for defining and
                      using factories - less error-prone, more explicit, and
                      all-around easier to work with than fixtures.}
   s.email = %q{jferris@thoughtbot.com}
   s.extra_rdoc_files = ["README.rdoc"]
-  s.files = ["Changelog", "CONTRIBUTION_GUIDELINES.rdoc", "LICENSE", "Rakefile", "README.rdoc", "lib/factory_girl/aliases.rb", "lib/factory_girl/attribute/association.rb", "lib/factory_girl/attribute/dynamic.rb", "lib/factory_girl/attribute/static.rb", "lib/factory_girl/attribute.rb", "lib/factory_girl/factory.rb", "lib/factory_girl/proxy/attributes_for.rb", "lib/factory_girl/proxy/build.rb", "lib/factory_girl/proxy/create.rb", "lib/factory_girl/proxy/stub.rb", "lib/factory_girl/proxy.rb", "lib/factory_girl/sequence.rb", "lib/factory_girl/syntax/blueprint.rb", "lib/factory_girl/syntax/generate.rb", "lib/factory_girl/syntax/make.rb", "lib/factory_girl/syntax/sham.rb", "lib/factory_girl/syntax.rb", "lib/factory_girl.rb", "spec/factory_girl/aliases_spec.rb", "spec/factory_girl/attribute/association_spec.rb", "spec/factory_girl/attribute/dynamic_spec.rb", "spec/factory_girl/attribute/static_spec.rb", "spec/factory_girl/attribute_spec.rb", "spec/factory_girl/factory_spec.rb", "spec/factory_girl/proxy/attributes_for_spec.rb", "spec/factory_girl/proxy/build_spec.rb", "spec/factory_girl/proxy/create_spec.rb", "spec/factory_girl/proxy/stub_spec.rb", "spec/factory_girl/proxy_spec.rb", "spec/factory_girl/sequence_spec.rb", "spec/factory_girl/syntax/blueprint_spec.rb", "spec/factory_girl/syntax/generate_spec.rb", "spec/factory_girl/syntax/make_spec.rb", "spec/factory_girl/syntax/sham_spec.rb", "spec/integration_spec.rb", "spec/models.rb", "spec/spec_helper.rb"]
+  s.files = ["Changelog", "CONTRIBUTION_GUIDELINES.rdoc", "LICENSE", "Rakefile", "README.rdoc", "lib/factory_girl/aliases.rb", "lib/factory_girl/attribute/association.rb", "lib/factory_girl/attribute/callback.rb", "lib/factory_girl/attribute/dynamic.rb", "lib/factory_girl/attribute/static.rb", "lib/factory_girl/attribute.rb", "lib/factory_girl/factory.rb", "lib/factory_girl/proxy/attributes_for.rb", "lib/factory_girl/proxy/build.rb", "lib/factory_girl/proxy/create.rb", "lib/factory_girl/proxy/stub.rb", "lib/factory_girl/proxy.rb", "lib/factory_girl/sequence.rb", "lib/factory_girl/step_definitions.rb", "lib/factory_girl/syntax/blueprint.rb", "lib/factory_girl/syntax/generate.rb", "lib/factory_girl/syntax/make.rb", "lib/factory_girl/syntax/sham.rb", "lib/factory_girl/syntax.rb", "lib/factory_girl.rb", "spec/factory_girl/aliases_spec.rb", "spec/factory_girl/attribute/association_spec.rb", "spec/factory_girl/attribute/callback_spec.rb", "spec/factory_girl/attribute/dynamic_spec.rb", "spec/factory_girl/attribute/static_spec.rb", "spec/factory_girl/attribute_spec.rb", "spec/factory_girl/factory_spec.rb", "spec/factory_girl/proxy/attributes_for_spec.rb", "spec/factory_girl/proxy/build_spec.rb", "spec/factory_girl/proxy/create_spec.rb", "spec/factory_girl/proxy/stub_spec.rb", "spec/factory_girl/proxy_spec.rb", "spec/factory_girl/sequence_spec.rb", "spec/factory_girl/syntax/blueprint_spec.rb", "spec/factory_girl/syntax/generate_spec.rb", "spec/factory_girl/syntax/make_spec.rb", "spec/factory_girl/syntax/sham_spec.rb", "spec/integration_spec.rb", "spec/models.rb", "spec/spec_helper.rb"]
   s.homepage = %q{http://thoughtbot.com/projects/factory_girl}
   s.rdoc_options = ["--line-numbers", "--main", "README.rdoc"]
   s.require_paths = ["lib"]
-  s.rubygems_version = %q{1.3.4}
+  s.rubygems_version = %q{1.3.5}
   s.summary = %q{factory_girl provides a framework and DSL for defining and using model instance factories.}
-  s.test_files = ["spec/factory_girl/aliases_spec.rb", "spec/factory_girl/attribute/association_spec.rb", "spec/factory_girl/attribute/dynamic_spec.rb", "spec/factory_girl/attribute/static_spec.rb", "spec/factory_girl/attribute_spec.rb", "spec/factory_girl/factory_spec.rb", "spec/factory_girl/proxy/attributes_for_spec.rb", "spec/factory_girl/proxy/build_spec.rb", "spec/factory_girl/proxy/create_spec.rb", "spec/factory_girl/proxy/stub_spec.rb", "spec/factory_girl/proxy_spec.rb", "spec/factory_girl/sequence_spec.rb", "spec/factory_girl/syntax/blueprint_spec.rb", "spec/factory_girl/syntax/generate_spec.rb", "spec/factory_girl/syntax/make_spec.rb", "spec/factory_girl/syntax/sham_spec.rb", "spec/integration_spec.rb"]
+  s.test_files = ["spec/factory_girl/aliases_spec.rb", "spec/factory_girl/attribute/association_spec.rb", "spec/factory_girl/attribute/callback_spec.rb", "spec/factory_girl/attribute/dynamic_spec.rb", "spec/factory_girl/attribute/static_spec.rb", "spec/factory_girl/attribute_spec.rb", "spec/factory_girl/factory_spec.rb", "spec/factory_girl/proxy/attributes_for_spec.rb", "spec/factory_girl/proxy/build_spec.rb", "spec/factory_girl/proxy/create_spec.rb", "spec/factory_girl/proxy/stub_spec.rb", "spec/factory_girl/proxy_spec.rb", "spec/factory_girl/sequence_spec.rb", "spec/factory_girl/syntax/blueprint_spec.rb", "spec/factory_girl/syntax/generate_spec.rb", "spec/factory_girl/syntax/make_spec.rb", "spec/factory_girl/syntax/sham_spec.rb", "spec/integration_spec.rb"]
 
   if s.respond_to? :specification_version then
     current_version = Gem::Specification::CURRENT_SPECIFICATION_VERSION