A mushroom!
or
Three. One to climb the ladder while the second kicks the ladder out from under her. And the third to say, "I knew that was too high for you dear."
or
Three: One to screw it in, and the other two to help him down off the keg.
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Can I have your hand, hand, hand, hand, hand, hand, hand, hand in marriage?
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but I couldn't find any.
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Because he was feeling crumby.
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If one side has one, the other side has to get one. Once launched, they cannot be recalled. When they land, they screw up everything forever.
or