Another in my long line of pong based obsession:
The chaos computer club has come up with a delightful use of cell phones and light switches. They've created a computer controller that can control all the lights in an eight story building in Berlin. This alone is cool.
That you could then dial a number on your cell phone, and play pong on the face of a building just stretches my vocabulary beyond my ability to gush appropriately.
I think I need to add a pong category...