Start out with a simple game, like hangman or something else w/ clearly defined rules and gameplay that mostly depends on guessing. Have people play it a few ti

Start out with a simple game, like hangman or something else w/ clearly defined rules and gameplay that mostly depends on guessing. Have people play it a few times, and then have everyone come up with and write down the rules. Emphasize the writing things down formally part, since that's the most basic type of programming. Have them play the game again, but this time using the rules they defined. You could give out awards for the kids who find errors in the rules. Try a different game (tic-tac-toe? rock paper scissors?) and repeat the exercise. Once they've figured out that, give them a bare-bones vocabulary (eg something like python, but don't tell them it's a programming language) to write the rules in.