This 1960s Italian Lambretta scooter ad is fantastic: it features a cast of "scientists" in a futuristic, Tomorrowland sort of labratory, doing a musical number about the Lambrett Twist, the dance inspired by the Labretta's steering mechanism.
(Thanks, Julian!)
Update: Cristian sez, "The scientists are the Quartetto Cetra, an italian famous vocal quartet established during 1940. They were famous too for their spoof of musical hit singles of 50/60, in RAI (italian Broadcasting Television)."
Update 2: Cristian has graciously provided a mirror of the file.