Plagiarised from the Richard Dawkins forum:
Richard Dawkins, Barack Obama and Jesus are standing by a river, wondering how to get across. Jesus suggests they all simply walk across the surface of the water.
Dawkins goes first, and to the amazement of the other two, runs lightly across the surface to the other side.
Obama follows him, skipping lightly across to join him.
Jesus takes two steps and falls into the water up to his neck.
Dawkins grins, turns to Obama and says "Good on you for not telling him about the stepping stones."
Obama replies "What stepping stones?"
