Source code of Robotab, an HTML5 multiplayer game demo by 20tab
Play online at http://robotab.20tab.com
At the moment the code is pretty much raw and undocumented (I'll take care of it in the future), but still easy to read.
You will find the most interesting part (server side game logic) inside robotab_bullet.py. The client side part (Three.js graphic and command handling) instead is inside robotab_bullet.js.