Building your own game controller!
Donn Morse created a slightly modified version of the XNA Racing Game Starter Kit to work with a custom game controller that has an accelerometer!
The sample driver supports communication between a Windows 7 application and the sensor. (Note that in addition to a dual axis accelerometer, the driver also supports a compass, a passive-infrared sensor, and an ultra-sonic distance sensor.)
The XNA Racing Game Starter Kit sample demonstrates how you can write a complete auto-racing game in C# with .Net. Included with this project are three updated source files and a COM Interop which let the game receive input from your game controller.