MySong: Automatic Accompaniment for Vocal Melodies
Just for a bit of fun, Microsoft Research appears to be making the move in to Pop stardom a little simpler. The research being done by this team takes the vocal melodies and song that a person sings in the microphone and creates a musical accompaniment to compliment the singing.
The video itself goes in to the details, but make sure you watch to the end to have a laugh at the various ways people have applied it.