While at the main menu, press L + R to access the Cheat Entry Screen.  Then, type in FISH EYE as a code.

Free Mode

While at the main menu, press L + R to access the Cheat Entry Screen.  Then, type in FREEALL as a code.

Party Motel Mode

While at the main menu, press L + R to access the Cheat Entry Screen.  Then, type in PARTY M as a code.

Play The Sims Mode

While at the main menu, press L + R to access the Cheat Entry Screen.  Then, type in SIMS as a code.