So, last night, I watched the 1980 movie Foxes, and in an early scene, I heard this real funky rock number, so after some trial-and-error, I discovered that it was a number by an obscure one-album rock band called the Beckmeier Brothers: "Rock and Roll Dancin'". I like it because it has a real Joe Walsh kind of vibe to it.
TRIVIA: I also found out that the late Johnny Hallyday covered it in French as "Qu'est Ce Que Tu Croyais".