I found out how to extract the track data from a copy of Rock Band 2. The data is in MIDI format. I wrote some C# code to translate the MIDI data into instructions for a robot. Then I used an AVR chip with a heavily modified version of my drum controller code to play back those instructions. The result should make the robot play any song in Rock Band automatically (cheating!!!). It worked to an extent, but super accurate timing became an issue. I learned a lot about making a good buffer system while doing this project. The instructions are transmitted via serial port from a computer, and the AVR reports back to the computer when it's buffer is less than 33% full to enable the instruction stream, and disables the stream when the buffer is 66% full. This way, the computer can be hit with unexpected lag and the robot will still work.
Sorry about the lack of details for this project, I don't want to put any more up because the project never performed perfectly (as shown in the video).