One of the largest Microsoft Open Source projects (previously known as ASP.NET Forums) Community Server :: Forums has just been released!
More details here:
A few tidbits…
- over 150 compiled server controls
- hundreds of thousands of lines of source code (C#) included
- localized in over 10 languages
- designed to run everything from small single server sites to large multi-server web farms, and the discussion platform used by sites such as http://channel9.msdn.com, http://forums.xbox.com, and http://www.asp.net/forums