A class was given homework to find out something
exciting and tell it to the class the next day.
When the time came to present what they'd found, the first little
boy the teacher called on walked up to the front of the class. He
picked up a piece of chalk, made a small white dot on the blackboard and sat back down.
Puzzled, the teacher asked him what it was.
"It's a 'period'," he replied.
"I can see that," said the teacher, "but what is so exciting about a 'period'?"
"Darned if I know," said the boy,
"but yesterday my sister was missing one,
Dad had a heart attack
and the boy next door joined the Army!