I forgot how awesome Dan Gilbert's talk on low probability, the lottery, terrorists, swimming pools, asthma, expected value, happiness and how to always do exactly everything right was.

He's a great speaker with awesome, vivid and colorful examples, and the talk is a succinct and cogent explanation for why the U.S. spends so much money on counter terrorism (and seems to have a obsessive fixation on airports in particular).

link: "how to do the precisely the right thing at all possible times"

Social psychology (does this technically count as such?) is so incredibly interesting.