Cheat mode:
     Hold  R and press Up, Triangle, Up, Triangle, Up, Triangle at the
main menu.

Cartoon track (Kiruna track in Singleplayer):
     Hold R and press Right, Up, Left, Circle, Triangle, Square at the
main menu.

Summer track (Calgary track in Singleplayer):
     Hold  R and press Triangle, X, Circle, Circle, X, Triangle at the
main menu.

Unlock ATV:
     Hold R1 and press Up, Right, Down, Up, Right, Down at the main menu.

Unlock Go-Cart:
     Hold  R1  and press Right, Right, Left, Left, Right, Right at the
main menu.

Demo mode:
     Hold R1 and press Up, Up, Up, Down, Down, Down at the main menu.