How would Valve's Portal 2 play if it was controlled with motion gestures on Kinect? It'd look a lot like this Kinect hack created by Brad Cooley.
Running off the FAAST toolkit that has helped make many unofficial Kinect hacks possible, Cooley was able to get a Kinect sensor to track his skeletal body and map the infamous Portal gun to his arm. Like most Kinect hacks, the workaround solution is a little laggy and doesn't run at full speed. Had Valve officially made it, I'm sure the geniuses over there could get the full game running properly. Still, it's a good proof-of-concept using Kinect in a game that's more hardcore than just Kinectimals or Dance Central.
Check out Cooley's nifty Kinect hack below and if you want to learn how to reproduce the hack yourself, you can find his email over in the YouTube video's description.