Five. One to change the bulb and eleven to say they could do it faster.
or
the barman says "Oi - get out! We don't want your type in here"
or
Six. One to turn the bulb, one for support, and four to relate to the experience.
or
The owner got tired of the (w)hole business!
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