Saw this though a Slashdot post, but Umbraco, our favorite open source .NET CMS is in the Codeplex Top 25 projects. More details here:
http://www.plentyofcode.com/2007/08/most-active-open-source-projects-in.html
Nice work Niels and crew!
PS - off to Italy for 3 weeks, so don't expect many posts in the coming weeks!