3. HashrSimple Hash extension to make working with nested hashes (e.g. for configuration) easier and less error-prone.
4. SteamHeadless integration testing w/ HtmlUnit: enables testing JavaScript-driven web sites
6. MinimalMinimal templating engine inspired by Markaby & Erector but much smaller and targeting Rails 3
10. Routing Filterrouting-filter wraps around the complex beast that the Rails routing system is, allowing for unseen flexibility and power in Rails URL recognition and generation.
11. Rails I18nRepository for collecting Locale data for Ruby on Rails I18n as well as other interesting, Rails related I18n stuff
16. capture stdoutAdds Kernel.capture_stdout(&block). Useful e.g. for testing command line tools
17. ripper2rubySimilar to ruby2ruby this library allows to parse Ruby code, modify and recompile it back to Ruby.