A web-browser based viewer for opensim/OpenSimulator
Your death sentence awaits...
An expanded XNA game creation framework
Communication Engine for Distribution Architecture
Uniform Database Abstraction for PHP Development
Embedded NoSQL object-oriented database engine for .NET and Mono
RuleInfer is an engine that processes rules.
A cross-platform game framework based on OpenGL and GObject.
Enterprise- level HTML5 application development platform
HTTP Bruteforcer
A Wargame
An open source skateboard games engine written in C# and .NET.
WGFX 2D Game Engine
Open Source Virtual World and MMOG Development Platform
https://github.com/horde3d/Horde3D