This is an entry in our Disneyland 101 Glossary: Disneyland Resort definitions in under 101 words, from Mouse Brief.
“Sh-Boom” Time is the moment each night when the neon lights in Cars Land in Disney California Adventure Park ignite for the evening. This brief special occurrence mirrors the scene in the Cars film where the main character, Lightning McQueen, is charmed when he witnesses the town of Radiator Springs practice the same tradition of turning-on their neon lights with the accompaniment of the song “Sh-Boom” by The Chords. This “Sh-Boom Time” is not listed in Disney California Adventure Park’s entertainment guide, but it regularly occurs just after sunset each evening.