My elementary school was swept with a yo-yo frenzy sometime around fifth grade. I have no idea where it came from or why it ended so quickly, but I later thought that it would make an interesting sociology study. On Monday we were playing basketball at recess, and by Friday every kid on the playground had a yo-yo and we somehow knew all the trick names and had established a new social hierarchy based on command of the yo-yo. Rich kids had the ‘Butterfly’ yo-yos which were easier for walk-the-dog type tricks, which gave them a bit of an advantage in scaling up their quiver of tricks more quickly. What did I learn? The rich get richer. It was good to get that one before sixth grade.