If anyone figures out the people tracking idea, I have another spin-off.

For those with small children, what about a small RF transmitting device (radio beacon) that can be clipped on their clothes? And for yourself, a small handheld digital compass-like device that can tell you the distance and direction they are from you.

Many people think those kiddie "leashes" are quite inhumane.

Roland
(i know this is swaying away from X-10)