Odamex is a free, cross-platform, modern client-server Doom engine
Cross-platform real-time strategy game (3D)
The Free & Popular Community git Server in a Complete Virtual Machine
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
shooter game in wild west atmosphere
A turn-based multiplayer shooting game in the style of Worms
Networked Jeopardy game
The SCND Genesis: Legends
Dueling Simulator for the Yu Gi Oh TCG