Opensource Created Custom Viewers For Virtual Worlds like SecondLife.
Combat Flight Simulator for LINUX. WW2. Network and VOIP. Open-source.
0 A.D. is a free, open-source, cross-platform real-time strategy game.
Grepolis utility
Viewer for Second Life and OpenSim virtual worlds
Star Trek Web browser game
Advanced Wasteland mission using ACE for Arma II
Frontend for Minecraft Server
SLiteChat is a completely open source text-only IM/chat client for use