Einsteins to Change Lightbulb

Q: How many Einsteins does it take to change a lightbulb?
A: That depends on the speed of the changer, and the mass of the bulb. Or vice versa, of course. Then it just might be easier to leave the bulb alone and change the room. It's all relative.

NASA Techs to Change Lightbulb

Q: How many NASA technicians does it take to change a lightbulb?
A: Seventy, and they plan it for two weeks and when they finally get around to it the weather's bad so they postpone it till next week. The lightbulb costs three million dollars.

Romanians to Change Lightbulb

Q: How many Romanians does it take to change a lightbulb?
A: None. Ceaucescu restricted them to use only one 40 watt bulb per family to save electricity.