3DTours is a C# 3D virtual reality tool based on the open source Irrlicht 3D engine and Microsoft .NET framework 2.0, can be used to demonstrate a tourism site, a building, an art gallery or whatever you can imagine of. Developed by Thai Minh Hoang Ha and Dang Duc Vinh.
Personal projects using XNA, C#, and luck. Every once and then I parse a BSP file or hack up some HLSL code.
XNA class library for supporting loading of Quake 3+ art content. Library provides XNA Content Importers for loading quake 3 contents (BSP, MD3, MD5Mesh etc)