Thirteen

A young man was strolling down a street. As he passed a large building with a fence around it, he heard a group of people chanting "Thirteen, thirteen, thirteen" over and over again. Curious, he tried to see over the fence, but couldn't. Then he spotted a hole in the wood. He put his eye to the hole. He just managed to spy some old people sitting in deckchairs chanting, before a finger came out of nowhere and poked him in the eye. As he staggered back, the old people started chanting, "Fourteen, fourteen, fourteen..."