You wouldn't realise he's wearing an artificial leg.
My selections. 25 Best Sites for Free Educational Videos. RefSeek's guide to the 25 best online resources for finding free educational videos.
With the exception of BrainPOP and Cosmeo, all listed sites offer their extensive video libraries for free and without registration. Academic Earth Thousands of video lectures from the world's top scholars. academicearth.org Big Think. All Videos. History. Science. Brain Pickings.