[Sister Havana]

My grade school best friend and I used to do this one late at night when we slept over at each other's houses:
We'd call some number at random from the phone book. When the person would answer, we'd use our sleepiest voices and say "I'm sorry to bother you, but your dog is barking at my cat and I can't get to sleep." Most of the time, the person would say "I don't have a dog." We'd perk up and say "That's OK, I don't have a cat!" One time, though, the guy who answered said "Fine, I'll bring the dog in!" and slammed the phone down.

This used to absolutely slay us.