In my youth I had a knack for starting daft crazes. My two favourites were:
1. Object Breaking: This consisted of breaking pencils with your head; starting with one, and steadily increasing the number of pencils until you couldn't break any more. This craze ended abruptly when one young protege rendered himself unconcious attempting to break a thick piece of plywood stolen from wood tech.

2. Noseology: The study of how far an object can be inserted up one's nose. The most popular items were Lego bricks, which were removed on every occasion by the school nurse with a pair of tweezers. In attempting to put my school mates to shame I managed to trap a kidney bean in my sinus which my sister informed me would grow into my brain and slowly kill me. Luckily, I sneezed it out a few days later. PHEW!