G-cluster is a Finnish company that has produced an interesting game system.
The system uses a cluster of servers that is connected to game systems via radio link.
The system allows people who are in the radio link range to play games with their PDAs, "smart cell phones" or laptops. The PDAs only act as dumb clients; the game sessions are kept on the server cluster. The traffic back to the client thing is basically streaming video.
The games, then, are normal PC/video games; It was pretty amazing to see an iPAQ running Quake and Tux Racer, at an acceptable framerate, in the demos!
Home page: http://www.g-cluster.com/