Three:
One to write the light bulb removal program,
one to write the light bulb insertion program, and
one to act as a light bulb administrator to make sure nobody else tries to change the light bulb at the same time.
or
Well, first let's talk about the concept behind this whole "light bulb" thing.
or
He had in his own pews.
or
It went back four seconds!
or
Just one, provided there is a programmer around to explain how to do it.
or
Because all his other wives support Hillary.
or