A little boy thanked his grandfather for the set of drums he bought him for his birthday. “They’re the best present I’ve ever had,” he said. “They’ve already earned me $80.”

“Wow!”’ said the grandfather. “You must have learned to play them real good!”

“Not really,” said the boy. “But Mom gives me $5 not to play them during the day, and Dad gives me $5 not to play them in the evening.”