"Smart Rooms" by Alex P. Pentland, Scientific American April 1996, pages 68-76
"In creating computer systems that can identify people and interpret their actions, researchers have come one step closer to building helpful home and work environments"
This is an older article but it has some very relevant ideas. They discuss using cameras to read human movement and behavior to interact with a virtual environment. The funny thing is this is becoming a reality this year when Microsoft releases "Kinect" for the Xbox 360 for Christmas.
I think this sort of interface is whats next for how humans will interact with computers. It opens a lot of new possibilities for how one's house can "see" it occupants and connect with them.