Ask HN: What are some good free resources to learn Ruby (not Rails)?

The following resources are good & FREE

    - tryruby
    - rubymonk
    - ruby.about.com
    - Programming Ruby(http://docs.ruby-doc.com/docs/ProgrammingRuby/)
    - http://www.codecademy.com/tracks/ruby
    - http://rubylearning.com/satishtalim/tutorial.html
    - ruby.learncodethehardway.org
    - rubykoans.com
    - https://learn.thoughtbot.com/ruby
    - http://iwanttolearnruby.com/
    - http://www.tutorialspoint.com/ruby/
    - http://ruby.bastardsbook.com/toc/
    - http://ruby-doc.org/
    - http://pine.fm/LearnToProgram/
    - http://mislav.uniqpath.com/poignant-guide/

Why's Poignant Guide To Learning Ruby (yes, that is the name...)