"Now son, you just tell that monkey to leave you alone because you need to sleep."

"I do, Daddy, but he won't."

"Well then you tell him that I'll come in and make him go away and that he should go bother some other little boy. Okay?"

So Jimmy told the monkey his dad's warning and the monkey sat and thought about it for a few minutes and said, "How about we play up till ten o'clock and then we'll both go to sleep?"

And that's what they did for years.