Crash Tag Team Racing

Enter at the main menu:

Chicken headed people:
Hold L1 + R1, press X, O, O, Square

Disable all head up displays:
Hold L1 + R1, press X, Square, Triangle, O

High speed:
Hold L1 + R1, press O, O, Triangle, Triangle

Japanese Crash Skin:
Hold L1 + R1, press Square, O, Square, O

Run into a car for an automatic KO:
Hold L1 + R1, press X, O, O, X

Toy block cars in single and multiplayer:
Hold L1 + R1, press O, O, Triangle, Square

 