Pro-lifers light bulb joke
Question: How many pro-lifers does it take to screw in a light bulb?
Answer: Two, one to do it and one to insist that the bulb was lit when the screwing began.
Answer: Nine-four to block the entrance to the room, four to hold up pictures of burnt-out bulbs, and one to try and convince the person with the new bulb to let the room stay dark.
Question: How many proofreaders does it take to change a lightbulb?
Answer: Proofreaders aren't supposed to change lightbulbs. They should just query them.