Straight from Mongolia, a list of the top 25 Microsoft open source projects:
It is nice to see the open source projects' progress in Microsoft world, especially it is been extremely fast growth after the Codeplex launched, and also GotDotNet suggests their hosted projects to move on to Codeplex. As you might remember, I have submitted a post about Codeplex a few weeks ago; Microsoft Open Source Projects. This time, it is proud to list most popular and active top 25 projects that has been hosted in Codeplex.
I'm not sure what his algorithm was for inclusion in the list, but there's some great stuff in there, from the ASP.NET AJAX Toolkit and the ASP.NET RSS Toolkit, both of which I've used, to cool stuff like SharpMap, a map rendering/display engine, and the intriguingly-named Elephant Game Framework for XNA. Read the whole thing...you're bound to find something of interest.