Best joke ever experianced?

Every friday the teacher asked the class a question. The student who got the answer correct didn't have any homework for the weekend. So little Johnny went home and painted two gold balls black. Just before the teacher asked the question on friday he rolled the golf balls to the front of the class, teacher picked them up and said "Ok Who's the comedian with the black balls?" Little Johnny stood up and yelled "Bill Cosby! See you Monday!"