[mc]

Begin with a problem then start with the thing that your users will see and work your way down the stack. New students enjoy the immediate gratification from changing a color, moving things around on the browser, or animating a great looking turtle. I recommending having a problem to work within as it provides constraints and a set of mini goals. "I need to take user input" then becomes "I need to process user input" then becomes "I need to put this user input somewhere" and once your friend visits each part of the stack, he can decide where he wants to spend time.

I didn't answer the "fun" part because it's not so great a leading indicator of career direction. Both sides have significant depth and breadth in terms of technical challenges and skill.