Thirteen

A young man was strolling down a street in South London.

As he passed a large building with a fence around it, he heard a group of people chanting "Thirteen, thirteen, thirteen, thirteen" over and over again.

Curious, he tried to see over the fence, but couldn't.

Then he spotted a knot in the wood, and put his eye to the hole.

He just managed to spy some old people sitting in deckchairs and 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, fourteen..."