Free, cross-platform 2D game engine powered by Haxe and OpenFL
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
GemRB is a portable open-source implementation of the Infinity Engine
PyMancala: A Python API for the Mancala game
The AWS GameKit Plugin for Unreal
ZED OS the clone of Windows XP
Character animation system for games and simulations.
Card/Tile Game play blending skill and odds
Play52 is a card game designed for iPhone and the iPod and PC