Fifty — one to screw in the bulb and 49 to guard him/her.
or
Because everything else on the plate is crackers.
or
They make used car salesmen look good.
or
An astronut.
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Just one more, guys, I promise.
or
Bar magnets have poor homogeneity.
or
Bozo The Clown has real hair on his head.
or
Five after one.
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A workaraunt.
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Roosters don't lay eggs!
or