Double Fine Happy Action Theater? Released! Trenched Iron Brigade: Rise of the Martian Bear DLC? Also released! Today! Right now! I mean, my lord, get on your Xbox and download them both!
Update: And if that wasn't enough for you, then PC fans will be pleased to hear that Steam is offering 50% off their "Double Fine Pack" -- Today only! That includes Costume Quest (with the Grubbins on Ice DLC) and the updated version of Psychonauts for your PC. Half price!
Believe it or not, I just got an Xbox 360 with a Kinect just so I could play this game. :)