A few months ago I found a big fat book about really disgusting science (worms, lice, vomit, etc.)that is really densely written and my son wouldn't usually look twice at. He keeps it next to his bed, reads it for hours, and regales us with gross tidbits that he has memorized. (Did you know there are more harmful germs in your spit than in your pee??)
There has got to be a special name for the buzz you get as an unschooling parent when something you laid out for your kid takes fire. For the satisfication of really top-rate detective work.
Such as "he likes this, he likes that, hmmm, maybe he'll like this!"
I feel like a million bucks. And so does he!