Today's xkcd strip got me thinking. What sort of weird Tetris or Tetris-like games are out there?

So far I've seen Tetoris (that Flash Tetris game with an enormous playfield), First-Person Tetris (someone should remake this in 3D where you are literally looking out from the side of the piece), a physics-based Tetris or Tetris-like where the pieces are really bouncy, and a Tetris tech demo with anti-aliasing, anisotropic filtering, HDR, bloom, refraction, ambient occlusion...

Oh, and KnP Tetris!

Anyone know of any others?
Hmm, maybe we should make our own weird Tetris knockoffs too, though that might be a topic for Locomotive Engineers.