OpenMoko is a mobile phone. The thing about this is that it runs Linux and a host of other open source software. There's even a developer version of the phone so you can get to work on making your new killer application for it. It's not even that expensive either at $300.
I wonder what weird and wonderful things the world will come up with for this phone. I don't use my phone for much besides making calls and texts, but I'd be interested to see what more imaginative cats come up with! ;-)