When I was a kid. I wanted an SNES just about as bad as anything. I loved playing Super Mario and F-Zero and Metroid and Contra3. My family would make trips to Walmart where they had a SNES kiosk. As long as there wasn't too long of a line I could play for hours on end. I would get a crick in my neck (staring at the CRT tube placed on a stand taller than me) and my thumbs and forefingers would be red and barely able to move.
This project could allow me to re-live my youth (at least the sore thumbs) on a modern computer.
It could also be a really fantastic first project for getting into microprocessors. The button presses are simply sent to the computer as keyboard presses and the accelerometer data sent over as mouse movements. Here is a video of one of the authors playing Portal with it (that one made my fingertips and wrist sore).
Thanks Adafruit and Teensy. :)
See Here if you just want to buy an adapter board (for a wide variety of consoles :) )