I don’t know for you, but, when I work, I like to have cheat sheets near me, just in case I need a quick answer.
For Ruby on Rails, I assume everyone knows the ‘I Love Jack Daniels’ (now aka Addedbytes) cheat sheet :
Click Here to download pdf version via AddedBytes.com
But this weekend I found 3 others cheat sheets on Dizzy :
Action Mailer Cheat Sheet (click to download)
Forms Helpers (click here to download)
Migration 2.0 cheat sheet (click to download)
Really gorgeous and useful, don’t you think ?