None. There never was any light bulb.
Notes: Probably the only really good light bulb joke of 1984.
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6: 2 to screw in the bulb and 4 to testify that it was lit from the moment they began screwing.
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Seven. One to change it and the other six to sing about how good the old one was.
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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.
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