I thought about it a little, I'd probably not let them program much in the beginning and simply create results that they can keep hacking on through a high level tool.

To that effect, I'd probably recommend at this time appery.io .. to make mobile web based apps, which also bring in data.

Appery introduces enough about building apps, as well as the data and logic flow in a browser that people can learn one language (javascript) to see what's possible and branch out from there.

What do you think? Feel free to get in touch.