Model rockets

Johnny bought a model rocket kit.
But his mother wouldn’t let him buy any of the model rocket engines.
“They’re dangerous,” she said. “You’ll burn the damn house down.”
So, Johnny came up with another way to launch his rockets.
He wove together a gigantic elastic catapult that he made out of smaller rubber bands and springs.
Then, he cranked it tight, shouted “FIRE!”, and kicked the trigger.
The catapult launched the rocket high into the air, striking a helicopter pilot in the head.
The helicopter spun and fell into the neighbor’s house.
After that, he took up model trains.