The first two indie bundles generated over a million dollars last year for charity. The first bundle of 2011 comes out today and includes Trine, Shadowgrounds, Shadowgrounds: Survivor, and a preorder for Splot. It also includes the game/source code for the unfinished project Jack Claw.
They are all DRM free and can be downloaded directly, or from Steam, Desura, and OnLive. PC, Mac and Linux builds available (except for Jack Claw).
Pay what you want. Give funds to charity. Shoot things in the face. What more could you want?
Check out the Humble Frozenbyte Bundle at www.humblebundle.com.