Short for a Light Bulb Joke. A sometimes offensive joke that follows the general pattern:

- How many something does it take to change a light bulb?
- Number. Short explanation.

Two examples can maybe help explain it:

- How many hardware folks does it take to change a light bulb?
- None. That's a software problem.

- How many jugglers does it take to change a light bulb?
- One, but it takes at least three light bulbs.

One of the largest and most widespread collections of canonical light bulb jokes is the one gathered by Kurt Guntheroth.