Opengate is a Jumpgate remake
X3D is the open-standard format for 3D graphics scenes on the Web.
RTSish Game Engine
A fast-paced free software rally racing game
Open-DIS implements the IEEE DIS protocol in multiple languages.
Physics Game like "The Incredible Machine"
OpenEstragon is a market economy simulator.
SuperWikia: The Runtime/Realtime Environment for Codesmiths
A libgdx pinball game.