Thanks to Pat for pointing me at refcardz

As they like to call it "FREE Cheatsheets for Developers";.

4-5 Pages of free PDF giving you an overview of a lot of topics, starting from Ajax, continuing at Windows Power shell and also covering topics such as Design Patterns.

Go get'em while they're hot! :D

p.s. if you don't want to click though all of those sites to get them all, I might be able to share it in ;)