Light bulb.
A voice from the back of the bar shouts back, "You don't have enough ammo, mate!"
Bingo!
None. There are no light bulbs in the closet. Another one: Why is Justin Bieber so pale? Because there's no light inside the closet
Well, you can sleep with a light on.
Why are you asking me that question Can't you see I'm busy!
None. Babies don't have the motor skills or the depth perception to change a light bulb.