A small application for as many platforms as possible (iphone, win, xbox, linux, android, nokia etc) which can save a very simplified recording of someone humming to one of their cd/mp3s. Once they have finished they are shown a worm graph of their deviation from the avarage hum for that song. People play to make their humming closest to the song / avarage. Players own points which make them look cool in facebook and other social media.
The data is stored and mined to produce the scores for pay games and music matching services (much more accuratley than current versions) + all kinds of music based information.
The format would need to be nice and small, as well as easy to produce. not sure how to do that.