Ask HN: My 16 year old brother is job shadowing me, what should I do with him?

I'm a UI Developer and my 16yr old brother is job shadowing me this week. The current project I'm working on uses backbone.js and I fear he will be lost if I try to explain it to him. He's had one semester of Java so far and knows HTML / CSS fairly well.

I'm open to any suggestions on how I should fill my day with him.