6: 2 to screw in the bulb and 4 to testify that it was lit from the moment they began screwing.
or
Two. One to change the bulb, and one to write a song about how good the old light bulb was.
or
Shamboo!
Frankenstein: Witch can you make me a lemonade?
Witch: Poof you are a lemonade!
or