XBox Controller as a SNES Controller
If you are into playing emulated Super Nintendo games on your Mac OS X laptop, but find the keyboard awkward to use, and have a spare Xbox controller, and a spare USB cord laying around … have I got a deal for you.
(I should preface this with using game emulators and and game ROMS is, sadly, of questionable legality)
Short and sweet: it seems XBox controllers (non 360) use USB to do their magic, so modifying an XBox controller to use with your computer is very simple. Just cut the XBox controller and the USB cords then wire them together (leaving out the yellow wire). The inside wire colors will match up so it shouldn't be hard, but here is a movie showing how it's done (ignore the driver part unless you are on windows).
Once your controller is ready, download the Mac OS X XBox HID driver. After it's installed you can find the settings in System Preferences.
Finally, fire up Snes9x, and go into Config > Configure Controllers. You should see the following:
In this screen click on a button (for example the purple up arrow) then press the corresponding button on the controller (the direction pad up button, or the joystick up). Once the controller is configured you're all set to play - and you didn't even have to ruin your original SNES controllers.