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

Cartoon track (Kiruna track in Singleplayer):
     Hold R and press Right, Up, Left, B, Y, X at the main menu.

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

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

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

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