Joel Ivory Johnson has written a great article on Codeplex showing how you can build a level applicatoin for the ZuneHD using its built in accelerometer. If you have not looked at ZuneHD yet you may not have known that you can write software for it using our XNA Framework. In addition to the accelerometer the ZuneHD also supports multi touch. Check out this indepth article here. In addition to supporting the ZuneHD our XNA development system is also supported on the Xbox 360. Still hard to believe you can code a new game using C# and XNA on your laptop and deploy it over to your Xbox 360 in the living room.
If XNA sounds interesting check out Dan Water's book on Zune game development using XNA Studio 3.0.
Microsoft Dynamics ISV Architect Evangelist