Da Boom is episode 03 of family guy season 03. It was originally aired on December 26, 1999.
Peter makes the family cancel their New Year’s Eve plans because he’s paranoid about the millennium. But when Y2K hits and the world is destroyed, all that remains standing is a Twinkie factory. When the Griffins set out to find the factory, they realize it’s the end of the world as they know it.