Open source library for N64 development
Open source library for creative expression on the web, desktop, etc.
A free 3D game engine to create games and realtimes scenes for Windows
Java decentralized cross-platform network multiplayer game engine
Multi-threaded 2D Renderer licensed under the Mozilla Public License
TurboSphere is an easy to learn and powerful JS based game engine.
A game development kit for Sifteo Cubes.
Hungry Hero is an open source Flash game built on Starling Framework.
DREAM is an Open Source GCS
A cross-platform Java 2D graphics library using OpenGL.