We got a surface in the office! I can't really talk about the project I'm working on, but I will say that I'm determined to get some version of the satellite tracker on it - It offers a very interesting interaction model that could be a fun way to visualize and interact with orbits.
One problem is that the SDK is under wraps so when you run into problems there's really not much of a community to turn to. The MS Surface developer's blog offers little in the way of hard examples, offering more of a list of cool stuff they're working on and why this thing is going to be cool when the masses get a hold of them.
I'd love to offer up some more info, but am under an NDA! Here's a little peek at our developer station until I can talk more.