Have you read about the new Power Toys for Visual Studio yet? Sara Ford talks about them a bit on her blog. These toys, tools really, have been released as shared source at the http://codeplex.com web site. Shared source means that the code is available and you can add to them yourself. In fact Sara lists several ways to get involved.
Why would a student get involved? Several reasons. One is to make the code into what they want it to be. Another is the chance to work hand in hand with the professinal developers of the Visual Studio team. If you are looking to make a name for yourself as a sharp developer and strong problem solver you way want to step up to the plate. Who knows where it might lead?
BTW the Power Toys themselves look interesting as they are. One that I want to spend some time with is the Managed Stack Explorer. Somehow I think that being able to look through the stack of a process could be a powerful learning tool. Are high school students ready for it or should it wait until college? What do you think?