Two. One to change the bulb, and one to write a song about how good the old light bulb was.
or
A pork chop.
or
Woke up in the fireplace.
or
He had no patients.
or
The wedding wasn't much, but the reception was incredible!
or
Twenty. One to hold the bulb, two to turn the ladder, and 17 to be on the guest list.
or