Hack your building! ("make the web physical" track)
Imagine you could contribute code to improve your building elevator. How would you prioritize it?
People will learn to fix the elevator first with their devtools changing the DOM+CSS manually, then with the browser console, then writing a simple artificial intelligence that takes care of elevators as people request it.
Groups of 3-4 working together to fix the elevator. Groups by level so that novices are together (and face+solve issues of same level together)
The outcome is the process. People will learn HTML/CSS/JavaScript/devtools through making/fixing.
People will be learning HTML, CSS and JavaScript as they go, following the gradual level of difficulty. Session hosts will help people as they get stuck.
A day after.
Organizations teaching code may be particularly interested in the simple exercise and gradual complexity approach of the exercise. Other than that, anyone can come and learn, regardless of their level.