SoapBox Car:
To unlock the Soap Box Car go to the Options Menu. Hold L1 and R1 and press additionally Triangle, Triangle, Square, Circle.


Homers car:
Complete all 10 missions in mission mode successfully. Choose the Car by selecting Homers picture at the car select screen.


New Year's Krusty Character:
Set the system date to January 1st. Choose New Year's Krusty by selecting the "?" at the character selection screen.


Halloween Bart Character:
Set the system date to October 31st. Choose Halloween Bart by selecting the "?" at the character selection screen.


Thanksgiving Marge Character:
Set system date to November 22nd. Choose Thanksgiving Marge by selecting the "?" at the character selection screen.


Christmas Apu Character:
Set the system date to December 25th. Choose Christmas Apu by selecting the "?" at the character selection screen.