Here's another great pun from Stan Kegel.
I took my two sons, ages seven and five, to the playground at our local park. My seven year old was very proud that he was able to read to his brother the sign with all the rules posted for the playground.
"1. Do not jump on the merry-go-round when in motion."
"2. Go down the slide while sitting only."
"3. Only one child on a swing at a time."
There were about twenty rules and the boys promised to obey them all, if I would trust them and let them play without me standing by to watch. They said that they were too old to be watched and their friends would tease them calling them babies if I stayed.
I made them promise to be good and obey the rules, and rejoined my wife preparing our picnic lunch. When it was time to get the children, I decided to watch them at a distance for a while to see how reliable they were in following my instructions.
I found that they obeyed most of the printed instructions. That is, all but one... They would each get on the tall semicircular slide and slide down head-first or backward.
Angrily, I walked to the children and escorted them over to the posted regulations. I asked my seven year old read to them aloud once again - paying special attention to the rules about the slide. Then I asked them what they had to say for themselves.
My five year old answered immediately: "Don't be silly Daddy - they don't use slide rules anymore. (By Stan Kegel)