Game engine supporting many 3D/2D formats and graphic effects
Asphyre is a cross-platform framework for Delphi and FreePascal.
Perl bindings to the Modern OpenGL API
3D .NET engine for Windows, Linux, Mac
A generic 2D engine for any kind of game
C++ game libraries plus server.
Extremely simple joystick rumble / vibration library
A graphics engine + toolkit.
Pear3DEngine is a modern and modular 3D development framework
Multi-Language Wrapper Collection for the Irrlicht Engine
The next generation mud is an open-source extensible, programmable mud