Five: One to change the bulb and four to pull the ladder out from under him/her.
or
One's a spineless, poisonous blob. The other is a form of sea life.
or
Because he wanted to draw the curtains!
or
One; she designs the bulb to crawl up the wall, unscrew the old one, and screw itself in.
or
No one knows. Republicans automatically disbelieve him, and no one can ever trust a stinking liberal anyway.
or
A porcupine with split ends
or