I stumbled upon www.archive.org, repository of classic cartoons and educational films.
The Coronet series of films is hilarious. Try this one out:
They’ve got old movies, old newsreels, government films, music, books … it’s a goldmine for history junkies, and it’s all free.
Edit: If you’re unable to watch the movie by clicking on the image, try one of the links that appear below it. They’re different file formats, and one of them will work on your computer if you experiment.