My fellow member Joe over at Golden Age of Hollywood posted this clip there recently and I can't get it off my mind. I'd seen it once long ago and then more recently at a friend's house in the film Stormy Weather (1943).
Cab Calloway, his band and the Nicholas Brothers dance team put on an incomparable performance. If you haven't seen it, do yourself a good deed and check it out. Music and dance in film doesn't get any better than this.
And that goes for Stormy Weather in general. As Wikipedia put it, the film is "a time capsule showcasing some of the top African-American performers of the time, [a time] when black actors and singers rarely appeared in lead roles in mainstream Hollywood productions, particularly of the musical genre."
I can't put it better than that.