Looks like another company has decided to cash in on the Dance Dance Revolution craze with a "fitness controller" for PS2/Xbox/etc. It's basically a giant joystick that you push against resistance to move in the game. It's not tied to any game in particular.
This looks incredibly stupid, and costs a mere $700-1200. But, hey, who knows... I'd rather play GTA3 or Halo than do HIIT.