Share 'Bad attempt at a joke...'

Saw this post from a friend (who I'd guess doesn't seriously believe in god anyway).  I'm guessing the moral is that there shouldn't be freedom of speech.  It's hard to reply to something so stupid, but I'm interested in hearing your ideas... A College Professor stood on his chair and said, "If GOD really exists, knock me off my chair." Nothing happened. The class was quiet. He said "See? I'll gi…