Programmers seem to live in a world of their own (as this site indicates), with their own vibrant culture - and their own premises and vocabulary. Once we've been in the field for a bit, we take a lot of things for granted. But I'm often faced with the question "What do you do?" Or "What is programming?"

I generally try to answer this with a small, often trivial, real-world example of how programming is prevalent in our everyday lives and keeps things running. The example I use most often is an elevator - someone has to program the logic of that... And I've seen elevators that are "smart" and ones that are quite backwards and foolish. (And you can easily understand if/decision and looping from that... incorporates a lot of important programming concepts in a very small example.) I've sometimes heard people use traffic lights as an example.

What example do you / would you use to explain the concept of programming to someone completely clueless?