What'd be cool is a program that'd play a sound file on continuous loop, and have sliders for adjusting pitch, tempo, and volume as it plays. Gradually tweak the tempo up as they get deeper into the adventure..
Well, you're joking, but most music editing software can do that. You would have to save the song with the increased speeds, but Cubase and Cakewalk can do that.
Well perhaps... depends on how you define 'big'. I am a bit of a penny-pincher so to me anything more than completely free starts requiring heavy justifications.