To unlock the following things, enter these codes on the "Cheats" screen:
OUTFITS: Brick City Clothes: R Trigger, Black, R Trigger, L Trigger, Y, X, L Trigger
Clowns: X, L Trigger, X, Y
Cowboys: Y, White, White, R Trigger
Elvis Clothes: Y, Black, White, Black, Black, White, L Trigger, Black
There are more outfits, but I'm not saying any more...
EXTRA BALLS: Black Ball: White, White, Y, Black
Normal Ball: R Trigger, X, X, L Trigger
Red, White, and Blue Ball: Y, White, X, White
GAMEPLAY CHEATS: Block Party (Extra blocking boost):R Trigger, Y, Black, White
Power Game (more power): White, Y, Black, Y
There's one more, but I'm not telling...