CTFs as you need them
Arianne is an engine to develop multiplayer online games like Stendhal
Full featured MUD server with all the trimmings.
JavaScript framework to build game engines, games, emulators and apps
JAVA websocket implementation for a bomberman-like game
3D .NET engine for Windows, Linux, Mac
LEGADEE (LEarning GAme DEsign Environment)
Battlefield 3 Remote Administration and Information PHP Class