Odamex is a free, cross-platform, modern client-server Doom engine
Java decentralized cross-platform network multiplayer game engine
The original Xivio.com World Server Core
Proxy for games that emulates network conditions like ping and lag.
A multiplayer First-Person-Shooter game built in Java 3D
Multi-user whiteboard emphasizing simplicity.
Free, open-source platform for running LEGO® SERIOUS PLAY® remotely