Most Interesting Way to Explain Subnetting

I was working with a junior (greener than grass in July) tech today and had to explain subnetting to him in terms he could understand.

My explanation was "That Pie that everyone loves that grandma makes, imagine instead of slices everyone just took a spoon to the center. That's what we are dealing with. What I am trying to do is make it into slices so everyone has their own slice." Site transitioned from /16 over the weekend to more manageable subnets in the /23 and /24 range.

So, what is the most interesting way you have had to explain subnetting so they understood the concept?