Basically, if Microsoft is sponsoring this whole thing, find a way to integrate their hardware and software in a way that will benefit both them and your school.
Whether that's Kinect (which was the first thing that came to mind, but probably the best avenue to pursue) or something else they make.
Also, you wouldn't need it in every class. For example, you could setup a fairly large display behind a glass wall so that no one could damage it, and then have some kind of maths or science games that are made for the platform. Even better if those games already exist and just have to be made to suite the Kinect type of interface. Kids could play against eachother and have competitions, etc. which makes it interactive, innovative, teaches them something and gives Microsoft good publicity.