Abyss Studio Game Engine - Open Source, commercial level game engine and multimedia components. Extensible, Modular, Abstract, Scripting and Portable Framework for all levels.
A real-time 3D interactive media engine written in .Net using C#. Rendering is a choice of OpenGL, DirectX, XNA or Pure software renderer. Uses Lua scripting but with use of interfaces any scripting language is possible. Cross-platform using Mono.