Student Showcase Winner, 2007 Independent Games Festival
In Opera Slinger, you sing opera--into a microphone. It's a quasi-beat matching game, but your score depends on hitting the right notes as well as singing them at the right times; before you play, you choose the male (tenor) or female (alto) role. Your "opponent" is controlled by the AI, and the game's conceit is that you are competing with him or her for the regard and adoration of the audience--which changes more in your direction the more accurately you sing.
Opera Slinger isn't quite a complete game; there are only a handful of arias included, and after playing it through, you may well wish there was more. But then, it was a student project, not a commercial game (and consequently is free)--and indeed won the Student Showcase at the 2007 Independent Games Festival.
Still, it's entertaining proof that there's more to be done with music games than whanging at a fake plastic guitar.