Only one, but it sure takes a shitload of light bulbs!
or
Two. One to assure the everything possible is being done while the other screws the bulb into the water faucet.
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When it came time to pay, the skunk didn't have a scent, the deer didn't have a buck so they put the meal on the duck's bill.
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Because he wanted sweet dreams.
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It wanted to be a watermelon.
or