Check this out. Looks like something that could be useful for this crowd in the future... Pretty inventive, I think.
http://www.theverge.com/2013/6/4/4397458/wisee-prototype-detects-gestures-from-the-next-room-using-only-wi-fi
http://www.theverge.com/2013/6/4/4397458/wisee-prototype-detects-gestures-from-the-next-room-using-only-wi-fi