If you are not familiar with Sandcastle, it is a tool which takes your source code XML comments and produces beautiful MSDN-style documentation.  Not so long ago, Sandcastle was pulled off of Codeplex because it was in violation of the Codeplex rules (in particular, the project didn't include source code).

There was a lot of debate about this (both externally and internally).  Personally, I was an advocate that we should maintain Sandcastle on Codeplex and include the source code.  I'm extremely happy to report that this is exactly what we decided to do:

Sandcastle : Sandcastle Source Code published in Codeplex