Jeremy McGraths Supercross World cheats and cheat codes for Gamecube

Enter the following controller combination cheats at the main menu.
If the cheat codes entered correctly, you will see the name of the 
cheat and you will hear a sound also. Re-enter the code to ddisable 
the cheat effect.

"Bouncy, bouncy" cheat:
Press Up, Up, Up, Y, Y, X, X for bouncy bike.

"Your head expands" cheat:
Press B, X, R, L, Right for bigger head.

"Tag you're it" cheat:
Press Z, X, Z, X to enable tag mode.

"Drink me" cheat:
Press L, Z, Left, Right, B, B to enable small mode.

"Need for speed" cheat: 
Press Down, Down, Down, L, R, Z to get infinite turbo.

"Feel lighter" cheat: 
Press Left, Right, Up, Down, B, B, B to enable low gravity mode.

Disable boundaries:
Press L, R, Z, L, R, Z

Unlock every bikes
Finish the hardcore part of career mode

Quick start:
Start your engine when the pre-race countdown reaches "3", then 
hold R2 when it reaches "1".