Loops - Radiolab

I'm a big fan of RadioLab.  This particular episode has elements appealing to my mathematical side --- how the concept of "zero" relates to loops and infinity, and a wonderful exposition on the mathematical concepts of undecidability and mathematical incompleteness.  As usual, the Radiolab folks find a way to present the information in a manner accessible by ordinary (educated) folks.  It's well worth an hour of your time.