How many developers does it take to change a lightbulb?

One, because developers are sensible and rational people.

None. It's a hardware problem.

Zero. We'd rather code in the dark.

four. one - tech.dir two - team lead. three - coder who will replace the bulb, and four - qtester will check if the light is on and everythng fine

It only takes one, but they had a four hour meeting about how to best build the device that does the spinning to screw it in.

The light bulb never gets changed because the PM constantly asks for status reports, the manager gives the dev 20 other light bulbs to change and constant changes from the client means by the time it's done, the light bulb is now an elephant.