Footage is a 1973 McDonald's commercial showing customers and McDonald's crew members dancing and signing as if in a Broadway musical. 

Everyone is pumped with energy. The song they're singing is the ever-popular refrain, "Don't you deserve a break today? - At McDonald's?!" 

Eventually, they all end up high kicking in the restaurant's parking lot before coming to a dramatic stop, holding their poses of exuberance for the camera for fame in perpetuity.