Reminds me of http://holiday2010.ogilvy.com
The game-engine, collision and logic run on
the server in JavaScript running on Node.js.
The clients are simply rendering information
sent from the server, and sending off keyboard input.
https://github.com/hyperandroid/CAAT/https://github.com/BonsaiDen/BiSON.js
http://developer.valvesoftware.com/wiki/Source_Multiplayer_N...