Twister!
or
A blackboard.
or
Clerk: "Yes, sir. What size does your alligator wear?"
or
Two. One to assure the everything possible is being done while the other screws the bulb into the water faucet.
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