Here's a use for your iPhone I bet you haven't tried: sticking it on a plastic gun and using it as a sight in an augmented reality game.
But that's exactly what you can do with the Appgun. When playing a game designed for it, it uses the camera to display what's in front of you, plus some aliens or whatever for you to shoot at. It seems kind of awesome! And it'll set you back $30 when it comes out in April, complete with a free game to let you shoot up your living room.