Opensource Game Studio
Y.A.G.A.C is a free open-source platformer game
Low-Level Game Engine for Retro Platforms
Portable game engine with main focus on point-and-click adventures
3D-Accelerated open-source DOOM engine
SJCE - free portable cross-platform graphical chess game, 100% Java.
Build Cross-platform Applications
Dizzy Omega - sequel of Dizzy Y game
3D driving simulation based on Open Dynamics Engine
C/C++ , PHP, PYTHON, 3D ENGINES, CHROME NATIVE CLIENT
scriptable game engine with built-in support for 2D graphics and sound
Sims 3 (and other) game package library
The ultimate 2D side scrolling engine. NOTE: Moved to GitHUB
starrydb is game server engine
Extensive Java chess database libraries.