When I was looking for a PHP and a MySQL Cheat Sheet at I Love Jack Daniels, I stumbled upon a Ruby on Rails cheat sheet. That was the time when I was giving consultation to a certain thesis group developing a web-based application. Since Ruby on Rails was new to me at that time and I really do not have the luxury to study it, I decided to postpone my quest.
I made a compilation of resources on Ruby on Rails earlier and these are:
Top 12 Ruby on Rails Tutorials
Ruby on Rails Cheat Sheet by Blake Kendall
Ruby on Rails Wiki
You could check out this page if you’d want to try RoR.