UCI chess engine
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
3D modeler, 3D game maker, 3D demo maker
A promising chess program
KotCity, an open source city simulator
Decorate your own virtual Christmas Tree
Cute 3D animated piglet who lives inside your phone
Cross platform 2D/3D game engine written in C++11 & OpenGL ES 2/3