For those who haven't heard of this add-on for Xbox 360 (I don't own one yet) and potentially PC in the future too:
This vid is a bit marketing spin, but gives some good ideas on its' potential uses. Full skeleton representation and prediction (for when limbs get hidden), including facial and speech recognition are touted to be features.
Imagine this, in a MMORPG or a chat messenger, taking note of your character stance, head tilt, eyes blink and gestures - from waving, clapping to dancing, your avatar will represent near exactly your way to everyone in cyberspace.
Is this the first step to bringing real-life character to online characters? Could this connect real to vitual people and finally get across online people are real people?
What types of games could be done? With the whole body as the controller, you can do a wide variety of things. Add in a standard controller too and things get very interesting...
Or will it lag too much? (Only time will tell there...)