Cheat mode:
Pause the game, then press: Right, Down, Right, Left, Right, Up, Right, Right.
Fast moves:
Be Ami or Daryl, Scoot beside a wall (in any level), then jump towards it, do a big move like The Bluenose, once you hit the wall you will bail your move but the points will still go up.
Unlock the "UltraFast Scooter":
In order to get the "UltraFast Scooter" you must enter a practice mode. You can be any character but you must pick the worst scooter. When you are in the practice, pause the game and press Triangle + Square + L1 + L2. Then go hit a jump and press L2 + L2 + L1 + Triangle + Square + Circle + R2 + Triangle before you hit the ground and you will unlock the UltraFast Scooter!