Metaphor is often a great way to reach the minds of the masses. I've done a lot of teaching, and writing, and it's a great tool to have at hand. Recently I've been using the metaphor of human anatomy to break down what's in the box - cpu is the brain, motherboard's the nervous system, ram is short-term memory, hard drive is long term memory, etc. It has both good possibilities and bad gray areas as an extended metaphor - what's the OS? Your culture? (Expatriates are dual-boot systems...) But I could still see an extended metaphor as a thread through the whole book, something to hold on to in the mind when people don't have experience actually holding the components. Anyway, I don't know if that's the kind of thing you're looking for, that level of simplicity, but in my experience, people respond well to the metaphor. It has helped things click for a few friends. Try it out on your friends. Hope it helps.