ted.com is my favorite website of the moment. I love the idea of essentially unrelated people -- arguably experts in their fields -- sharing ideas. In a lot of ways the more diverse the topics the more I like it.
On a related note, open space meetings also seem very cool, but I haven't participated in one yet. In general, I just like the idea of smart people from different fields sharing what they know, preferably without any hidden sales agenda (one problem I do have with a few presentations on ted.com).