There's still time left! Tyson has offered up some of the most philosophically profound notions I've probably heard since Sagan.

http://www.youtube.com/watch?v=w-uZZ7RdL5E

He has an amazing talent to boil down complex science into engaging communications that regular 'ol folks like myself can understand, yet still rich enough as to make me think about the topic for a terribly long time afterwards.