Unlock all locations:
Enable the Cheat Gnome code, then pause the game and quickly press Black, Down, R, L, Down, Y.

Unlock all objects:
Enable the Cheat Gnome code, then pause the game and quickly press Black, Up, Y, Down, R.

Unlock all Social Options:
Enable the Cheat Gnome code, then pause the game and quickly press L, R, A, Down, Black.

Unlock Team Picture:
Enable the Cheat Gnome code, then pause the game and quickly press R, Black, Down.

Boost your fun rating:
Buy the aromaster and place it in your bedroom. Everytime you go to bed turn it on to "Lavender & Marjoram". Put a burgular alarm in your house because that will be the first thing a burgular goes for.