I came to the Arduino because I was asked by a friend to look at the programming for some gimmicks he wanted for model aircrafts. If you look at starting posts in the "Project Guidance" section, most start with:
I want to control my turbine car/aquarium/camera/projector/light gimmick/servos/garden/hydroponics/steel mill ...
- or -
I have seen a cool watch/PoV/robot/rocket launcher/blinking jacket / sensors inputs I want to recreate - or -
I bought/inherited/found a description of a thing that works mostly, I just want to ...
And then they go on that they think the Arduino is the choice and how to get started with the tutorials, code fragments and circuit droppings they found on the Internet to make it happen. They don't really care about the Arduino itself, it just looks like the easiest way to get what they want.
The really great thing about the Arduino community isn't the the quality of information available, it's that in the beginner forums people get answers how to move closer to their goal. People get the feeling, that they aren't left alone utterly confused and bewildered.
To come back how to get people, specially children involved, is to do things with them they care about. And if those things need some microprocessor control to become better, you have your opening for the Arduino. It really doesn't matter what it is.
Korman