Kinect Party, Double Fine's upcoming mini game compilation for Xbox Live Arcade using all of the Kinect's abilities (and the sequel to Double Fine Happy Action Theater, which was released earlier this year) will be released on the 18th of December.
Even better, Microsoft's Major Nelson announced on his blog that Kinect Party will be free for a two week period upon it's release from December 18-December 31. In 2013, it will be sold at its regular price of 800 Microsoft Points ($10 USD).