[Jpoliachik]

Put on a "hacking" demo by using chrome debugger / inspect element to modify html. Ask kids who their favorite celebrity / athlete is, pull up their twitter and edit the tweets to say "Joe is so cool!", etc. Load the school's webpage and change the names of teachers. Make it goofy.

[justsomeguyhi]

I've used in-browser HTML editing in elementary school classrooms to great effect. A great trick is to "hack passwords" by typing in a password (will be represented by dots), then change its "type" attribute from "password" to "text"