Deals don't get any better than free, and when it comes to games as good as Psychonauts, it's an outright steal to get them for absolutely nothing! If you're a PC player and don't already own the game you need to jump on over to the Humble Bundle Store and pick up your free copy of the game right this instant.
Seriously quit screwing around and pick that up, you can watch this video to see what you're getting into later.