The ever-generous Hans Perk has posted a video of the Mickey Mouse cartoon The Pointer which includes an audio and visual representation of the click track used to time the cartoon. He has also included the animator identifications with each shot, so you can watch animation by Frank Thomas, Ollie Johnston, John Lounsbery, Norm Ferguson and others.
I showed this to my animation lecture class of over 100 students. I had previously discussed the use of the metronome and I've also been talking about beats in terms of walks and runs. The Pointer doesn't rely on music as heavily as Thru the Mirror, another cartoon that Hans has posted with an accompanying click track, but you can still see the animation working with the beats on walks, runs and even hand gestures.
This is an incredibly powerful tool for organizing the timing of a cartoon and guaranteeing that your animation will synch tightly to a music track. Hans and ASIFA-Hollywood have brought this approach back from the dead and we owe them a debt of gratitude.
Don't just look at this stuff and file it away. USE IT! Your films will be better for it.