Online Course Lecture at Harvard

Online Course Lecture at Harvard

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Ted
There's a host of videos from TED conferences and every one of them is worth watching. I can strongly recommend the talks by Richard Dawkins, Craig Venter, Hans Rosling and many others.
 
Reference:
http://stackoverflow.com/questions/24319/where-can-i-find-good-technical-video-podcasts-or-videos-for-download