Forum Thread: Coolest Pocket-Sized Gadget?

I was wondering, what's the coolest pocket-sized gadget you've ever seen? 

I was at a tech fair once, and they had a little cube thing. When you pressed this button, it could be pulled apart into six different little screens, each one having a camera. The screens interfaced with each other, and could be shared with up to six people as visual communication devices. Of course, they cost about 10 thousand dollars a cube ><