I thought it was pretty interesting to hear that Microsoft is releasing this new .Net technology under the Microsoft Open License. It was announced on Scott Gu's blog (no big surprise there, he is the source for all the best information about ASP.Net MVC)
I think this is a great move on Microsoft's part. It puts them on the same playing field as other MVC technologies that are making headway into the developer market. From talking to some of my friends it works a lot like Grails and Ruby right down to the file layout. Sure all three have some differences, but overall they sound pretty similar.
Having become such a big fan of MVC I'm hoping that this move makes this new Microsoft Release successful.