Lights Out & Arduino

So, I'm deciding right now which Arduino board to pick up (between NG and Barebones), and one of the projects I want to start out with is interfacing with the light/sensor board from an old Lights Out game - so, a 5x5 matrix with buttons on each 'node'. It has 23 leads on the ribbon between the sensor/light part and the logic part - so any ideas how I would start out decoding it and starting to make an interface (and expanding the outputs of Arduino?)

Thanks, this stuff is pretty awesome

That depends - can you get into the lights out box? If so, tracing out the cable is a matter of using a dvm to follow the wires out to the connector, and taking good notes. If you need help, there's a good reverse engineering tutorial on tinaja.com.