I brainstormed for a while and came up with an idea which ended up being a sort of musical game. In the game, at the middle of the screen would be a frame and there would be a picture of a composer flying across the screen and stop when you shoot with the gun. The object would be to try to get the composer to land in the frame and music would start to play (written by said composer). Depending on how close you were to getting the picture to stop at the correct place, the music would change. If you were very far off the music would sound wrong - perhaps being out of tune or some parts playing in the wrong key or different parts not being in time with one another etc. If you are close to the target, it would sound slightly better, and if you are perfectly accurate, it would sound perfect.
Here is the Max/MSP patch unfinished as it currently is:
In order to execute this idea I had to learn about how the lcd object works, how to make sprites move across a screen, how to get break up midi information and edit individual parts and how to split Midi into different channels using Max/MSP and Logic.
I have also bought one of these:

And hopefully soon I'll be able to use it for connecting my playstation controller to the PC and using the "HI" object in Max to get data from it.