Anything you like, he can't hear you.
or
Two — one to change the bulb, and one to write a song about how good the old light bulb was.
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2 years old.
Cow: "Mooooove over"
Sheep: "Naaaaaaa."
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Does it have to be a light bulb? I've got this neat candle holder...
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A crossing guard.
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Seven. One to change it and the other six to sing about how good the old one was.
or