Thanks to my father-in-law, who has mentioned this several times over the last year or two, I have become somewhat addicted to TED talks. Basically TED is an annual conference (plus spin-offs) full of very clever and interesting people speaking (or performing) on pretty much anything they want.
Browse through the archives and you will find Al Gore telling us how to combat climate change, geeks demonstrating spectacular user interfaces, a neuroscientist talking about what it is like to have a stroke, a presentation of images from the Cassini-Huygens mission to Saturn and my new hero, Clifford Stoll, talking about... well... pretty much everything and anything.
Inspiring stuff, this, and I've barely scraped the surface so far.