[artlogic]

I have to second the deck of cards approach. One particularly effective exercise is to hand someone a shuffled deck of numeric cards and ask them to write down a process for sorting them, using only the concept of bigger or smaller. Given about 20 minutes, most people will come up with selection sort on their own.

It's this sort of introspection that's key to understanding computers. We abstract large chunks of computational thinking naturally. It's essential to be able to ask yourself, "How am I really doing this?" - and to come up with an answer.

edited slightly for grammar