Two — one to screw it most of the way in and the other to give it a surprise twist at the end.
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When you are eating a watermelon.
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What's the use, they'd still have bear feet
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1,000,001: One to change the bulb and 1,000,000 to rebuild civilization to the point where they need light bulbs again.
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Two. One to screw it in, and one to stab the other in the back and take all the credit.
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Only one, but it sure takes a shitload of light bulbs!
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The cow that jumped over the moon
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