> Not that I have heard of it before this post, though.

Tetris Friends does this for their multiplayer games[1][2]. When you "play against people", what you're really doing is playing against their replays. It's quite clever, and it had me fooled for a while while I was still in college.

[1]: http://harddrop.com/forums/index.php?showtopic=1434 [2]: http://www.destructoid.com/tetris-friends-has-instant-six-pe...