How many X are needed
to change a light bulb?

How many nuclear engineers?

How many US Presidents?

None, the constitution says that only Congress can screw in light bulbs, so only Congress is responsible for the dark, which is why we need a Constitutional ammendment.

How many bureaucrats?

  1. Two. One to assure everyone that everything possible is being done while the other screws the bulb into the water faucet.
  2. Five - one to change the light bulb and the other four to fill out the Environmental Impact Statement.
  3. One to spot the burned-out bulb, his supervisor to authorize a requisition, a requisition typist, twelve clerks to file the requisition copies, a mail clerk to deliver the requisition to the purchasing department, a purchasing agent to order the bulb, a clerk to forward the purchasing order, a clerk to mail-order a receiving clerk to receive the bulb....
  4. Seven-- one to supervise, one to arrange for the electricity to be shut off, one to make sure that safety and quality standards are maintained, one to monitor compliance with local, state, and federal regulations, one to manage personnel relations, one to fill out the paperwork and one to screw the light bulb into the water faucet.
  5. Two - one to screw it in and one to screw it up.
  6. Just one. But she gets promoted three times before she finally finishes screwing it up.
  7. None, we contract out for things like that.

How many Quality managers?

We've formed a quality circle to study the problem of why lightbulbs burn out and to determine the best thing we as managers can do to enable lightbulbs to work smarter, not harder.

How many programmers?

None. It's a hardware problem.

How many GNU/Linux users?

And finally:

This joke was mailed to the FSF by its author Andre Machado. The Free Software Foundation claims no copyright on it.

Tons of others there, and even a dedicated wikipedia page.