To see how long he slept.
or
I said, "Are you two an item?"
or
To log on.
or
A crossing guard.
or
He presses the paws button.
or
They both dribble.
or
On the latest episode of "Celebrity Apprentice", Donald Trump fired himself!
or
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