You need:

- an iPad >= 4.2.1
- node.js
- socket.io (server + client)

Test URL (sorry the socket server won't be online all the time): http://cubiq.org/dropbox/sb/
Lock the device rotation before trying. What you'll see is a red ball you can crontrol by tilting the iPad.
If other users are connected you'll see them as grey balls. Communication happens thanks to websockets.

*Not ready for production*, this is just a proof of concept.

To-do:
- would be nice to add collision detection between balls.