Remember F-Zero GX for the GameCube? Fun game, and as it turns out, it's been hiding the arcade version in it this whole time. F-Zero AX was developed at the same time as GX, and both versions are essentially the same.
Arcade players were given exclusive race tracks, which GameCube players would be able to gain access to after inserting their memory cards into the arcade units. Easier said than done, as it was hard to find the cabinet at arcades.
Now a decade later, some hackers found out that the entire arcade version is actually hidden away on the GameCube disc. Even better, they've created a way for players to access the arcade version. You just need an Action Replay or Gameshark, and a PAL or NTSC version of F-Zero GX to access the arcade game. The Cutting Room Floor lists the codes you'll need in order to access the hidden content for those of you that still have your GameCube collection. I still have mine!