+1 for the DOM Inspector. I have found that kids LOVE pulling back the curtain on a website to see the wizard and play with the code. A fun activity is to have them go to a news site and have them edit the headlines and replace the images to silly things and take screenshots to share with their parents. What really impresses me with this exercise is how quickly some kids will figure out some intermediate hacks when they learn how easy it is to google the things they want to do.

Another suggestion that works for the same reason is to give kids code to play with. I've wasted 20 minutes of class time having kids write a three line "Hello World!" javascript program from scratch. All this did was irritate and bore the kids out of their minds as they struggled with syntax and hunt-and-peck typing.

Instead, when I give kids a great big block of javascript code that does something fun and animated, those kids will go wild with it. This is because changes to different variables can have big effects. They quickly learn to read the code and identify what different parts do. They break the code, and you show them how that's a good thing and how easy it is to revert it back so that it's working again. Code should be a playground. Give the kids a rich playground to run around in.