NINE!
It takes four. One to screw in the bulb, and three others to watch and say, "Really dude, you look huge!"
By holding the bulb up to the socket and waiting for the world to revolve around them EDIT: Rip inbox EDIT 2: Thanks for the gold!
Herr Kutz (This was funnier when I was half asleep this morning)
Kindling.
Three; one to drop the bulb and two to yell "pick it up pick it up!"
They grab the stack of un-signed adoption papers, stand on top of them, then proceed to change the light bulb.