The folks behind Light Table.
It's a game! A multiplayer racing platformer (thinks of it as mario, with colorshifting racing against luigi).
Only tested in Chrome.
The game mostly walks you through things itself. Race to the end, don't step on mines, and use your color shifting abilities to either make obstacles hollow or solid to help you get through the map.
All art original by ibdthor, game code by ibdknox, site by MarielBellmaker