John Travolta, Mick Jagger, and Barbra Streisand are the celebrities supposedly spotted by Scrappy at the movie premiere.
The motif clearly inspired by the popular Disco Craze of the late 70s. The fictional movie premiere is a for a movie called Hair Grease Fever, combining Hair (1979), Grease (1978), and Saturday Night Fever (1977). The song the Sparkles rock group are recording is clearly based on The Bee Gees' 'Staying Alive', the SNF theme song. One of the names Scrappy shouts out when star spotting at the premiere is "Travolta", i.e. John Travolta who starred in SNF and Grease.
Sundown Blvd., where much of the action takes place, is a parody of Los Angeles' legendary Sunset Blvd.