A simple in-process semaphore using C#
   Creating a semaphore to limit a given number of threads accessing a resource in a process.
   http://www.codeproject.com/csharp/inprocsemaphore.asp

C# Code Demos
   Demos of working C# solutions, featuring XML, reflection, SQL and WinForms.
   http://www.meissnersd.com/csharp.htm

C# Code Samples
   Small example programs in c#, each showing a concept: plugin, parser, morpher.
   http://spiet.ath.cx/c-sharp/

ExoEngine
   A C# OpenGL 3D game engine. Written to show that C# can in fact be used for real-time 3D game engine development. [Open source]
   http://www.exocortex.org/3dengine/

Open Source Software in C# (C-Sharp)
   Directory of open source software focused in C#.
   http://csharp-source.net/

The Code Project
   Formed to provide developers with a place to meet and exchange ideas. Intents to provide the resources needed to help developers in their day to day programming, as well as helping them keep up to date with the latest technologies.
   http://www.codeproject.com/csharp/