The Gizmondo is a handheld gaming-esque unit similar in shape to the (eww) N-Gage, but similar to the PSP (supposedly). You know, all the trendy stuff like Bluetooth, GPRS, GSM, etc. etc.
However, the cool thing is its GPS support. The unit has a built-in GPS receiver and there is apparently an upcoming game "Colors" where teams will run around capturing areas (real geographic areas), perhaps like Light-cycles? Also, You can apparently "fence off" an area that the Gizmondo can't leave, or it will SMS an alert to you (another phone or what? I'm confused) and then shut-off.
However, both of these are obviously limited by GPS reception. How good is it to have this kind of "Security" if you can't rely on actually getting reception? Does it shutoff when it doesn't have a signal? I doubt it.