rdoc_osx_dictionary
rdoc via Apple's Dictionary.app
Automatically builds and installs an Apple Dictionary with all rdoc nicely formatted.

Inspired by: http://priithaamer.com/blog/ruby-on-rails-dictionary-for-macosx
Get The Code
If you just want to use rdoc_osx_dictionary, you can install it via RubyGems:gem install rdoc_osx_dictionary
If you want to hack on rdoc_osx_dictionary, clone it from GitHub:
git clone git://github.com/seattlerb/rdoc_osx_dictionary