C-SPAN Archives Online
Well, most of them anyway. The C-SPAN Video Archive has posted all programs since 1987; the earlier ones require more work and will be posted as they are able. Currently over 160,000 hours of programming is available.
There is a lot of functionality there: embedging a video in a web site, emailing a link to the video, posting it to Facebook, tweeting it, details about the program, who was in it, a transcript, tags,related programs, and information on purchase. Wow! The current programming seems to be posted in a timely fashion; at the end of the day today, I see 2 videos from this morning already there.