Supercross Circuit Codes -

Big helmets:
Enter BIG_HELMETS as a code to unlock a "Big Helmets" selection on the bonus game options screen.

Headless riders:
Enter SLEEPYHOLLOW as a code to unlock the "Headless Riders" selection on the bonus game options screen.

Invisible bikes:
Enter FLOATING as a code.

Indo:
Press Up + Square during game play to op a wheelie on your front wheel.

Hint: Double points:
Find a big jump and jump it, and press trick button(s) until the small oval icon appears in bottom left corner. Release the buttons until both hands and feet are on the bike, then press the buttons to repeat the same trick. Release the buttons before you land to get double the points. This does work for every trick.

Hart Attack:
To do a Hart Attack (Indian Air), do a Superman Seatgrab and press Brake to bring the front end down. This is also works when you do a Flat Whip, hold it long, and press Brake to do an Extended Whip.