Funny Joke

A teacher tells the class if they can get the right answer to a question that will be asked every Friday, they can get the Monday off. The first Friday, she asks the class, "How many stars are in the universe?" No one can answer. The next Friday, she asks, "How many grains of sand are on Miami Beach?" Again, no one can answer. Finally, a boy gets a bag full of ping-pong balls painted black. The teacher on the 3rd Friday says, "Now for your question..." and the boys purposely spills the bag of ping pong balls everywhere. The teacher madly asks, "Who's the comedian with the black balls?" The boys replies, "Bill Cosby! See you Tuesday!"