Built to be ease of use, with no programming knowledge, Multi-platform
A traditional top-down OpenGL car racing game
Open Source 3D Game Engine
Free strategy browsergame engine.
Multimedia asset management and manipulator for Étoilé
C++ game libraries plus server.
A 2D Adventure Game & Engine
A generic 2D engine for any kind of game
The free and Open Source hockey simulator
LAIR is a Sandbox Dungeon Crawling Game
Library for creating turn-based games with simultaneous moves.
Modular Gaming Open Source Persistent Browser Based Game Framework
TurboSphere is an easy to learn and powerful JS based game engine.
TR Game Engine allows you to develop your game quickly and easily.
Take the chess graphism, and use it with a chess engine.
Classic backgammon in fantasy setting with a lot of missions.
Pygrid is an open-source and cross-platform pygame/python 2D engine.