None. They will never find one that burned as brightly as the first one.
or
When it's going cheep!
Did you hear the one about the crow and the telephone pole?
He wanted to make a long distance caw.
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Two. One to change the bulb, and one to write a song about how good the old light bulb was.
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The disk-o!
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A guy who has never been hit with a dictionary.
or