BrainPop.com is my favorite for animated educational movies. It's designed for kids (but no need to tell that to the adults) and has a variety of movies available FREE to explain a variety of subjects in humorous and easy to understand dialog. Here's just a few of their selections: Civil War, Nano-technology, Hurricanes, Robots, and Geometry.
You can also purchase an annual subscription for family, homeschooling, classroom, etc. The subscription allows you to watch all their videos, plus have access to related quizzes and activities.
Check out the Prelinger's Collection in the Internet Archives. You can view and download vintage videos like "The Librarian" a vocational guidance film from 1947... remember those voice overs? You can even find the original Jam Handy animated production "A Ride For Cinderella" from 1937 -- Cinderella relies on a Chevrolet to get her home by the strike of midnight.
At George Lucas' Edutopia.org, look for videos on teacher development, technology integration, project learning, and student assessment. Excellent resources for all teachers and school administrators!
The History Channel's website offers full episodes of Ancient Discoveries, Cities of the Underworld, Military Dogfights, Jurassic Fight Club, The Universe and more. You can also out their special interactive Presidents section for a limited time (through Feb. 2009) - it's chock full of Presidential bios and related info.
At Free Science Videos and Lectures, free video categories include animals, astronomy, chemistry, water life and weather. Did you know rats laugh when you tickle them? Or that there are seasonal cycles on Mars? You would if you spent some time here!
Discovery Channel video clips and full episode videos including the popular Shark Week and Planet Earth clips. Ever wonder how to get rid of a beached whale (think large explosion)?
And at National Geographic you can enjoy the amazing clips from destinations around the world, designed to educate kids and adults alike on the wonders of our world, or see full episodes on timely topics such as Animal Rights. ** Check out the video clip (4 min.) World Without Humans -- what would happen if mankind disappeared from the Earth.
You can also see videos especially for kids (click on the Kids link) like Gorilla in The Greenhouse, an 8-min animated video designed to teach kids eco-friendly energy concepts.