Idea Spark Mp3 to Wake is an idea that came to me from a Brainy Gamer podcast I listened to on the way to school about audio and sound-effect based games. AudioSurf was one of my favorite games on steam a few years ago, and I thought the concept was executed very well. Your game is inspired by the music, but it doesn't punish you for not memorizing the song like the "Guitar Hero" series does. It is like a casual integration that is pleasing and refreshing.
Concept The basic concept is this - you are a wake-boarder in a giant wave pool (like a water park). The pool is also an endless flow system (think flow rider or endless swimming lane). Now, the waves in the pool are proportional to the audio levels of the music. When I imagine it, there is basically a wave-form that matches a local average of a Music EQ Visualizer.
Here is a rough sketch of my idea done in paint.net. Nothing crazy advanced. You can clearly see the wake-boarder, the wave system, and the mp3 w/EQ visualizer onscreen. After looking at this image, I've decided the best name for this game is probably audio-surf, but it's already been taken :p.