Just announced by Rob Howard of Telligent Systems (and former caching guru from the ASP.NET team at Microsoft): 

One of the largest Microsoft Open Source projects  (previously known as ASP.NET Forums) Community Server :: Forums has just been released!

More details here:

http://forums.asp.net/Forums/ShowPost.aspx?PostID=457530#457530

A few tidbits...

Enjoy :)

[Rob Howard's Blog]