A free 3D game engine to create games and realtimes scenes for Windows
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
Modern 3D engine and IDE written using C# and C++.
A 2D game engine and level editor
IRB is a game creation toolkit
3D .NET engine for Windows, Linux, Mac
.NET - VISUAL BASIC NVIDIA +ATI PHYSX SLIMDX DIRECTX 9 -ENGINE/WRAPPER
XNA based game engine completely written in c#
3D Interactive sandbox environment
Pear3DEngine is a modern and modular 3D development framework
A game engine in java for 2D strategy games
DREAM is an Open Source GCS