Madden-type NFL gameplay simulator except you control a piano-playing ghost who lives in the bleachers. The way you play the piano affects some aspects of game play including on field play, the weather, the crowd sentiment, how happy the players are. Boss battles: you must fight off rival ghosts in piano battles. Perhaps the piano playing mechanic is similar to how guitar hero works.
Walking simulator / sims style game where you play a character named Dave and you can do whatever you want. MMORPG? Every character is a Dave?
F-15 Adventures: Animal Crossing style game but you play as an F-15.