Free and open source real-time strategy game
Cross-platform, open source, and super fast MUD client with scripting
FlightGear Flight Simulator: free open-source multiplatform flight sim
Play Fighting Fantasy fan stories on this simple engine
an osm openstreetmap 3D / bing maps car / flight / ballon sim game
LGPL jquery plugin for desqchess
EPIC is an indepth Multiplayer Strategy RPG Web Game