I enjoy watching the speakers because I feel that I learn something new, or that I feel smarter after watching some of the videos. If you've never heard of it, it's definitely worth checking out:
http://www.ted.com/

There's something on there for any person. Highly interesting.

I've seen some of them. It's too bad a lot of those ideas haven't made it out to the public yet. Either not enough support or too costly at first. One of my recent favs was the guy demo-ing the Wii controller in virtual space and creating a digital drawing board from it.