I have a few.
When I was 10, I thought it was the height of hilarity to steal a “Home for Sale” sign and put it in up at a church that was across the street from my neighborhood. Yuck-yuck - God’s home is for sale! Get it???
A few years later, a friend of mine got upset that his neighbor had a better lawn than he did. So, chemically induced, we go out one night with some of the cheesiest flower-seeds-in-a-$.50-pack and plant them in their flower bed. Since I lived in a completely different neighborhood, I never saw the carnage, well, bloom.
When I was 12 it was 1979 and two Popes died within a month of each other. I told a friend of mine, who was VERY susceptible to Nostradamian claims (her mom was an avid Nat. Enquirer reader, back when it was qwality), that it was predicted that if two Popes died within a month of each other, the world would end the following Friday, at 12:00 noon.
She believed me, like I knew she would. She told everybody in the school, which was a completely unexpected benefit: you have no idea the inner joy I felt when somebody came up to me a few days later and said “Didja hear? According to the Bible the world is going to end during lunch tomorrow because two Popes died!” “No, really!” “Really! Bobby told me!” (I didn’t tell Bobby and had no idea why he was spreading the rumor, but God favors the fortunate. Or something like that).
So, sitting in the cafeteria that fateful morning, the weirdest thing happened… the entire room, full of 200 or so kids, grew quiet. It was about 11:56 and everybody stopped speaking and started to look at the clock. The teachers (who sat on the stage (the cafeteria doubled as an auditorium)) were looking about, trying to figure out what was up (I’m sure that some of them knew, but there were a number of puzzled glances from some of the more clueless ones). The clock slowly inched towards 12:00… waiting, waiting, the entire room in deep silence.
Finally, sometime between 12:00 and 12:02, a few people let out some nervous laughs, the kids started talking again, and life resumed its normal course.
It was the greatest joke I ever perpetrated on anybody in my entire life. And it was a good lesson on human gullibility.