Odamex is a free, cross-platform, modern client-server Doom engine
TKD Scoring Wi-Fi Server supporting Android and IPhone clients
Free MMORPG
C/C++ , PHP, PYTHON, 3D ENGINES, CHROME NATIVE CLIENT
Java decentralized cross-platform network multiplayer game engine
Star Trek Web browser game
The original Xivio.com World Server Core
Proxy for games that emulates network conditions like ping and lag.
EPIC is an indepth Multiplayer Strategy RPG Web Game
A multiplayer First-Person-Shooter game built in Java 3D
Multi-user whiteboard emphasizing simplicity.