Back To Dave's Future
S5:E1
1987
IMDb
A wild ride on a merry-go-round sends the Chipmunks back to 1962. They meet a younger Dave. Without the boys' help in winning a band contest, he will spend his life as an accountant. When they are spun into the present, Alvin isn't sure whether he visited the past or bumped his head in a fall off the merry-go-round.