Q: How many modern artists does it take to screw in a lightbulb?
A: One, but all he does is set a jar of urine in the center of the room while a crowd of critics and university art professors stand around in a dark room stinking of urine applauding and convincing everyone that he has challenged our definition of screwing in a lightbulb.
That is an original Barefoot Justine Joke, bub!
Barefoot Justine 
There is a Russian joke about modern art. It runs like this:
“A cleaning woman in the Museum of Modern Art mistook modern art for rubbish and tossed it out into the trash.”