Ok, I know the wiimote works with the PC, and its easy to interface the nunchuk using i2c too, but there is something more cool about an even MORE DIY approach.
Roll on Starlino’s USB HID gamepad.
I love the fact its so simple, and the code is available. Its quite well done and the HID aspect means no messy drivers!
Squashing it into the middle of a Wii Wheel was icing on the cake for me :p