Boards
Unlock all of the other boards by achieving new levels of rank.
Third board
Achieve the rank of rookie; to unlock the third board.

Fourth board
Achieve the rank of sensei; to unlock the fourth board.

Fifth board
Achieve the rank of contender; to unlock the fifth board.

Sixth board
Achieve the rank of natural; to unlock the sixth board.

Seventh board
Achieve the rank of star; to unlock the seventh board.

Eighth board
Achieve the rank of veteran; to unlock the eighth board.

Ninth board
Achieve the rank of champ; to unlock the ninth board.

Tenth board
Achieve the rank of superstar; to unlock the tenth board.

Eleventh board
Achieve the rank of master; to unlock the eleventh board.

Costumes
Unlock the other costumes by performing all of the various colored tricks.

Third costume
Complete all green circle tricks to unlock the third costume.

Fourth costume
Complete all blue square tricks to unlock the fourth costume.

Max Stats
This code has to be entered from the Options Menu. Enter the Options Menu and hold all four shoulder buttons (L1, L2, R1, R2) and enter in the following code:

X, X, X, X, X, X, X, SQUARE.

There should be a tone to confirm that the code worked.

Unlock Characters
Win 1 Gold Medal to unlock Jurgen.
Win 2 Gold Medals to unlock JP.
Win 3 Gold Medals to unlock Zoe.
Win 4 Gold Medals to unlock Hiro.

Unlock It All
Access the Options Menu and hold all four shoulder buttons (L1, L2, R1, R2) and enter in the following code:

DOWN, LEFT, UP, RIGHT, X, CIRCLE, TRIANGLE, SQUARE.

Every Track, Outfit, Board and Character will be unlocked.

Unlock The Hidden Tracks
Beating all of the races in the World Circuit will open the Aloha Ice Jam. This course is located on an iceberg in Hawaii. Beating all of the showoff events will open the Pipedream course.
Beating the Aloha and the showoff event on the Pipedream course will open the last course called Untracked. This course is a freeride down the side of a mountain. SWEET!!

Unlock the Running Man Cheat

Access the Options Menu and hold all four shoulder buttons (L1, L2, R1, R2) and enter in the following code:

SQUARE, TRIANGLE, CIRCLE, X, SQUARE, TRIANGLE, CIRCLE, X.

View All Of The Hints
This code will allow you to view all of the hints prior to racing a course. You will want to turn cheat off eventually, do so by repeating the code in the options screen. To enter this code, access the Options Menu and hold all four shoulder buttons (L1, L2, R1, R2) and enter in the following code:

CIRCLE, X, CIRCLE, X, CIRCLE, X, CIRCLE, X.