Rinari Is Not A Ruby IDE.
Well, ok it kind of is. Rinari is an Emacs minor mode that is aimed
towards making Emacs into a top-notch Ruby and Rails development
environment.
IMPORTANT NOTE: The only currently-supported installation method is
via package.el, via Marmalade or MELPA. While other methods might
work, they are unsupported.
For a screencast of Rinari see
http://vimeo.com/2854412
For the latest version see
http://github.com/eschulte/rinari/tree/master
For somewhat outdated installation instructions and documentation see
http://rinari.rubyforge.org
For discussion of Ruby on Rails related Emacs development see
http://groups.google.com/group/emacs-on-rails