Just found out some cool news a little while ago: the ASP.NET team graciously released the source code for their new wicked-cool framework on Wednesday. You can get it at their CodePlex project http://www.codeplex.com/aspnet (and here's a link directly to the download page).
This is a great development in the ongoing push that Microsoft seems to be making to become more and more transparent... or at the very least more agile. And, I must say - I do like it! So, if you haven't gotten a chance to play with the MVC framework stuff yet, go grab all the bits; if you have already been playing with it, now you can check out the source, too!