DriveThruRPG/RPGNow does some pretty amazing charity releases. Here is another good one.
The Colorado Flood Relief Bundle.
For $20 you get over $200 worth of PDFs.
There are a lot of great games in this bundle too. Capes, Cowls and Villains Foul, Slasher Flick, Icons, Mutants & Masterminds, material for Deadlands, Savage Worlds and more.
A lot of great stuff. You really should pick this up.