Brewster Kahle's Internet Archive organization has a freely accessible moving images archive.
Why do I care? Because a historian I'm working with, while a great guy, seems a bit touchy about copyright on the materials we're going to use. (related to 1909 Plan of Chicago). Heck we're not even sure what the rights will be for the stuff.
One of my theories is that software can help build, organize, and direct an open inquiry community. Of course a reasonable body of interesting content is needed. I think the Prelinger Archives might qualify. And no permission required to work with it!