Alice laughed: "There's no use trying," she said; "one can't believe impossible things." "I daresay you haven't had much practice," said the Queen. "When I was younger, I always did it for half an hour a day. Why, sometimes I've believed as many as six impossible things before breakfast." ~ Lewis Carroll from Alice in Wonderland
Combine GPS and SMS and you get GPS.pi an application that constantly updates you on your friends' current wherabouts. Sounds like a perfect stalker toy to me. [Check it Out]