Oh Yes! The ASP.NET source code is now available. Read more at ScottGu's blog. I like open source, no complaints.
Next Steps: Our plans are to release regular drops of the source code going forward. We'll release source updates every time we do official preview drops. We will also release interim source refreshes in between the preview drops if you want to be able to track and build the source more frequently.
We are also hoping to ship our unit test suite for ASP.NET MVC in the future as well (right now we use an internal mocking framework within our tests, and we are still doing some work to refactor this dependency before shipping them as well).
Link to ASP.NET MVC Source Code Now Available - ScottGu's Blog