Well, it would go something like this. First off, get a song to play, but change the chord on it. Like let's say, This is Halloween. Change it from a minor chord to the exact opposite major chord. It will sound much different. And I think this is one of Josh's, so I am not sure if it's ok to use it. I'm just giving an example.
Oh yeah, and the name of the song can't be on it either

. Contestants will have to figure out which song is being played.
Btw, I don't know how to get a midi into another chord(unless it's sibelius 4 demo or finale notepad demo). I have a few songs from people, but I would have to take off the name of course...