Note: this list was born in the FB group Ruby Programming Language
Commonly used resources are found here: http://iwanttolearnruby.com/
Codecademy - http://www.codecademy.com/tracks/ruby
Code School - http://www.codeschool.com/paths/ruby
Data Structures in Ruby : http://www.brpreiss.com/books/opus8/
First Edition Programming Ruby: Pragmatic Programmer's Guide - http://www.rubycentral.com/pickaxe/
Hackety Hack - http://hackety.com/
LearnStreet - http://www.learnstreet.com/lessons/study/ruby
Learn Ruby The Hard Way - http://ruby.learncodethehardway.org/book/
MacRuby - http://macruby.org/
Nettuts+ Ruby for Newbies Sessions - http://net.tutsplus.com/sessions/ruby-for-newbies/
New Boston Videos - http://thenewboston.org/list.php?cat=50
O'Reilly Net Ruby (Last post in 2008) - http://oreillynet.com/ruby/
RubyGems - http://rubygems.org/
RubyMotion (Ruby for iOS Programming) - http://www.rubymotion.com/
Ruby Conference Videos - http://confreaks.com/events
Ruby Documentation - http://www.ruby-lang.org/en/ and http://ruby-doc.org/
Ruby Kickstart - http://ruby-kickstart.com
Ruby Koans - http://koans.heroku.com/
Ruby Forum - http://www.ruby-forum.com/
Ruby Monk – http://rubymonk.com/
** Ruby Notes - http://rubylearning.com/satishtalim/tutorial.html
Ruby Online Quiz/ Exam - http://rexaminator.com/
Ruby Regex – http://rubular.com/
Ruby Study Hall - http://www.rubystudyhall.com/
Ruby Quiz - http://rubyquiz.com/
ShowMeDo Ruby Videos, Tutorials & Screencasts -http://showmedo.com/videotutorials/ruby
StackOverflow Ruby -http://stackoverflow.com/questions/tagged/ruby
Try Ruby - http://tryruby.org
Why's Guide to Ruby - http://mislav.uniqpath.com/poignant-guide/
Eloquent Ruby (Addison-Wesley), Russ Olsen - http://eloquentruby.com/
I Love Ruby http://is.gd/ilr2013
Programming Ruby (Pragmatic Bookshelf), Dave Thomas, Chad Fowler, Andy Hunt - http://pragprog.com/book/ruby3/programming-ruby-1-9
The Ruby Programming Language (O'Reilly), Yukihiro Matsumoto, David Flanagan - http://shop.oreilly.com/product/9780596516178.do
GNU Emacs (Text Editor, OS independent) - http://www.gnu.org/software/emacs/
Komodo (IDE, OS independent) - http://www.activestate.com/komodo-ide
Notepad++ (Text Editor, Windows) - http://notepad-plus-plus.org/
Pry (IRB Replacement/REPL, Unix) - http://pryrepl.org/
RDE (IDE, Windows) - http://homepage2.nifty.com/sakazuki/rde_en/index.html
RubyMine (IDE, OS Independent) - http://www.jetbrains.com/ruby/
RubyInstaller (Windows) - http://rubyinstaller.org/
Sublime Text 2 (Text Editor, OS independent) - http://www.sublimetext.com/2
TextMate (Text Editor, Mac OS X) - https://github.com/textmate/textmate
Vim (Text Editor, OS independent) - http://www.vim.org/
Aptana Studio for Ruby - http://www.aptana.com/products/radrails
http://rubyfanboy.tumblr.com/post/27974525043/ruby-online-resources
And of course...
** COURSES at RubyLearning
http://rubylearning.org