You can unscrew a lightbulb.
On a steampunk bike the gears don't do anything.
A pencil has a point.
None, they arrest the room because it's black.
At least two, but they have to be pretty small to fit.
An unemployment line.(:
It taint yours and it taint mine :D (Puns for the win :D)
She delivers.
A pregnant woman is in Labour
One, but when he unscrews the bulb, the lights go out and your xbox is gone.