Head to the extras section of the main menu and insert the following code, which will give each of your characters infinite power: Circle, Left, Right, Circle, Square, L1.

To unlock all Lisa-related outfits and trophies, insert the following code while browsing the main menu: Square, Triangle, Square, Square, Square, L3 (click left analog stick).

To unlock all of Marges trophies and outfits, head to the games main menu and insert the following password: Triangle, Square, Triangle, Triangle, Square, R3.