Beyond Belief: Candles in the Dark
Here is a website that I think should be at the top of your most frequently visited.
It is the Science Network, http://thesciencenetwork.org/intro. There are many fascinating videos, conferences (the Beyond Belief Conference for instance). For my educator pals here is a place to find challenging videos for your high school level students, and of course undergraduates.
Click on the title of this article to go straight to the site.