Another Johnny joke...
Little Johnny's teacher declares in the class - "On Friday evening I will ask a question. Anybody who can answer that correctly can have the following Monday off from class". The entire class waits eagerly for Friday. Come Friday evening, and the teacher asks "How many stars are in the sky?". Of course no one can answer that correctly, and they all go home dejected. Comes another Friday evening, and the teacher asks "How many grains of sand are there on the beach?", and no one can answer that either.
Fed up with this, little Johnny thinks hard and gets an idea. He obtains two ping-pong balls and paints them black all over. The following Friday, just as the teacher is about to ask a question, Johnny, who's sitting in the back of the class, lets go of the ping-pong balls. They bounce all the way up to the front and come to rest at the teacher's feet. Really pissed, the teacher asks "Allright!! Who's the comedian with the black balls??". Up goes little Johnny in a flash.."Eddie Murphy, see you on Tuesday."