One, although it's probably screwed in too tight anyway.
One. They stick the bulb in the socket and wait for the world to revolve around them!
One. He is drunk, and he tells the bulb to screw itself.
Sikhs.
Two. One to change it and one to put some chips with it.
1 and 12 people to say how inspiring it was
All of them. One to hold the bulb and the rest to screw the world.
A: Deterrent.
How many pessimists does it take to change a light bulb? None - it's probably screwed it too tight anyhow!