A Microsoft patent, filed in March 2010 but only publicly released last week, is called PARENTAL CONTROL SETTINGS BASED ON BODY DIMENSIONS. It's about using tech like Kinect to automatically restrict content on a PC or Xbox depending on who (or what) the camera sees in the room.
Basically, it would use a camera (Kinect is never specified, but come on, it's Microsoft) to determine the size of the people standing in front of it. If it detects adults, then the console or computer can play adult content. If it detects kids, no dice. If it detects adults but then kids walk into the room, it can switch over on the fly.
If you're a giant kid, you're in luck. Conversely, if you're a tiny adult, you might want to switch it off.
PARENTAL CONTROL SETTINGS BASED ON BODY DIMENSIONS [USPTO, via Geekwire]