Microsoft's updated Xbox Live Marketplace with demos for Kinect Joy Ride, Rock band 3 and Apache: Air Assault.
Of course, you'll need Kinect and some form of instrument peripheral to sample the first two.
We reviewed the former earlier this week and found it to be the weakest title of Kinect's launch line-up. On the contrary, Rock Band 3 is excellent. Apache: Air Assault is an Activision game we've yet to sample, so let us know what you think.