Alternative Teeworlds Client with many exciting features!
Free MMORPG
JAVA websocket implementation for a bomberman-like game
The original Xivio.com World Server Core
Modular Minecraft server plugin - commands, events, ...
A lame multi-user dungeon engine.
Multi-user whiteboard emphasizing simplicity.
Battlefield 3 Live Action Addon for IRC Eggdrops
SLiteChat is a completely open source text-only IM/chat client for use