The first exercise any animator gets. I did mine in 2001 and re-did it nicer just now. They say in the early days of Disney they would give the fresh animators the bouncing ball exercise and depending on what proclivities they showed (draftsmanship, creativity, timing, weight...), that would determine what department they went to (breakdown, ink, story, character, effects, etc).
Helped my buddy Nader out on a music video shoot.
It was about the worst night of my life... standing in a forest-park in Inwood for 5 humid hours with feral bums and hungry mosquitoes around... but hey, the lighting DOES look great.