Guitar Hero 2 for the Xbox 360 game is on sale for only $1.99! The game is a couple years old now, but it was one of the most popular and top selling games. The deal is only valid for the Xbox 360 (No PS3 or Wii) and is only for the game (no guitar). The sale ends August 5, 2010, but they have limited quantities and I think this will sell quickly.
You can buy it online here or try to find it at one of their local stores.