Happy Friday the 13th. It's a celebration for some, while for others, it's a day to watch over their backs. But how did the superstitious traditions get started? The reigning theory goes back to the Bible during the time of Jesus and the Last Supper. There were 13 attendees, including Christ's betrayer, Judas Iscariot. There's also the claim that France's King Philip IV arrested the Knights Templar en mass on Friday, October 13, in the year 1307. In more recent times, attribution has been given to a 1907 novel titled Friday The Thirteenth, in which a Wall Street broker takes advantage of superstitions to create a market panic on the day. Then there are the movies to really hammer that terror in. Do you act differently on Friday the 13th? What do you do?