If you're not already familiar with TED Talks, you're missing out big time! TED stands for Technology, Entertainment, Design, and Wikipedia provides a great description:

The lectures, also called TED Talks, cover a broad set of topics including science, arts and design, politics, culture, business, global issues, technology and development, and entertainment. Speakers have included such people as former U.S. President Bill Clinton, Nobel laureates James D. Watson, Murray Gell-Mann, and Al Gore, Wikipedia co-founder Jimmy Wales, and Google co-founders Sergey Brin and Larry Page.

I used to catch these when they occasionally spread online to sites like Digg, but recently I've started watching a lot of these since they're only 20 minutes long, and there's all kinds of topics so you're sure to find something that interests you. There's a technology demo/explanation of how Brad Pitt's face was completely CGI in the first half of Benjamin Button (embedded below, gets really interesting starting at the 9-minute mark), Bill Gates talking about eradicating malaria around the world (this one became popular due to his releasing mosquitos into the audience saying "why should only poor people catch malaria?"), a cool technology called Siftables, and tons more.

It's costs $6,000 a year to be a member of TED and attend the conference, so it's awesome that they've been putting all the talks online for free since April '07.