The Bushnell BackTrack is a GPS enabled device that allows you to set three points of interest and then find them again. So, for instance, you could mark the place you parked your car and then consult the device when you return to the parking lot.
Holding it horizantally, an arrow will indicate what direction your car is, and the distance in yards to it. Just follow the arrow and you're back where you parked.
It works only outdoors (which is generally true of all GPS devices) and is a little large for my tastes - about the size of an Olympic medal. So it's not something you'll carry in your pocket. But it might be nice to carry in your glove compartment for the next time you park in overflow parking at the Giants game.
It also works as a digital compass.
Runs on two AAA batteries, not included.
Click here for company link.