Two. One to assume the ladder and one to change the bulb.
A': None. If the government would just leave it alone, it would screw itself in.
or
Does it have to be a light bulb? I've got this neat candle holder...
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Wet.
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Two. One to hold the bulb and the other to rotate the planet.
or
The ceremony was rubbish - but the reception was brilliant.
or