Want to get Psychonauts for PC for free? Well, your ideal response should be "no thanks, I've already got it, but I appreciate the generous offer", but in case you have a friend whose life might benefit from some Double Fine in his/her life, GameTap are now offering it for free.
You have to sign up with them, but that doesn't cost anything. They also offer Sam & Max: Abe Lincoln Must Die! for free too, but that's been done. I also should point out that there are other great free games to choose from (STALKER, Deus Ex, Thief 3, Tomb Raider Legend, Earthworm Jim etc), but we don't care about those.