I'd find Bret Victor's stuff interesting at that age and maybe the coding made by jtnimoy for Tron Legacy too. Anything from Siggraph. Cool dataviz. Or I don't

I'd find Bret Victor's stuff interesting at that age and maybe the coding made by jtnimoy for Tron Legacy too. Anything from Siggraph. Cool dataviz. Or I don't know. Wireshark. But the comments in here that are question/answer driven are great depending on the group of kids.