The new "Rise of the Martian Bear" downloadable content for Iron Brigade is available as of today for 400 Microsoft Points. With it comes 80 additional pieces of loot, four defense missions, two survival missions, and a boss encounter. This seems like a must-download based on the premise alone.
In other titillating Double Fine news, Costume Quest and Psychonauts are half off on Steam right now, and Happy Action Theater is live for Kinect owners. We'll have a review up later this week. If you end up getting the game, be sure to reenact the ending of Terminator 2 in the lava activity.