It was only in his late twenties that America’s favorite brainiac began to seriously embrace his love of trivia. Now he holds the “Greatest of All Time” title on Jeopardy! Steve Levitt digs into how he trained for the show, what it means to have a "geographic memory," and why we lie to our children.

The families of U.S. troops killed and wounded in Afghanistan are suing several companies that did reconstruction there. Why? These companies, they say, paid the Taliban protection money, which gave them the funding — and opportunity — to attack U.S. soldiers instead. A look at the messy, complicated, and heart-breaking tradeoffs of conflict-zone economies.