Two. One to take out the bulb and drop it, and the other to try and sell it before it crashes (knowing that it's already burned out).
or
Woke up in the fireplace.
or
1,000,001: One to change the bulb and 1,000,000 to rebuild civilization to the point where they need light bulbs again.
or
A river.
or
Superman can fly, but a fly cannot superman!
or
Wet.
or