Ranger GPS system. which, if it does everything it's supposed to, sounds pretty sweet. The unit plugs into the GBA slot of your DS Lite (and presumably your old DS Phat), features a u-blox GPS module, support for Google Earth and Google Maps and even packs a rechargeable battery.
Sadly, the price remains a mystery, which doesn't really matter as the unit doesn't appear to be available anywhere just yet. Let's just hope it releases before E3; LA traffic is a nightmare.