cheat sheets.

See:
http://www.yup.com/articles/2007/01/31/no-reservations-about-keywords-in-ruby-on-
ails (created 31 Jan 2007)

Includes: 
Reserved Words in Ruby on Rails
Other Problematic Names
Magic Field Names
Reserved Words for Various SQL Databases

See also: http://wiki.rubyonrails.com/rails/pages/ReservedWords (last updated 7
Oct 2008, as of this writing)

See also also: cheat ruby_keywords