It was a pretty good baseball season -- especially if you're a fan of the Yankees, Rays, Twins, Rangers, Reds, Braves, Phillies, or Giants, all of whom made the playoffs. But the post-season just opened with a telling event, a no-hitter pitched by the Phillies' Roy Halladay, which shows what's been missing all season: runs.

Steve Levitt talks about why the center cannot hold in penalty kicks, why a running track hurts home-field advantage, and why the World Cup is an economist's dream.