Buy Stuff For Free:
On the main menu, press L + R simultaneously, then type FREEALL.

Unlock 2 Player Mode:
On the main menu, press L + R simultaneoulsy and type MIDAS.

Unlock First Person View:
On the main menu, press L + R simultaneoulsy and type FISH EYE

Unlock Motel (2 Player Mode):
On the main menu, press L + R simultaneously and type PARTY M.

Unlock Play The Sims Mode:
On the main menu, press L + R simlutaneously and type SIMS.