It may not have much real world use right now, but the guys at Parrot are doing some cool stuff with Augmentated Reality and un-manned vehicles ...

So what is it? A radio controlled Quadracopter controlled via an iPhone, which has cameras built into either end and which relay the live footage back to the iPhone controller in real time, which in turn overlays augmented reality gameplay. Single and multi-player.

Sounds like a mouthfull right? True, but it's a great example of combining tangible physical objects with emerging software...and it's simple once you see it working:

More info can be found at Parrot's homepage here.