One of the things I wish my parents had done when I was little was take us out to the state parks, or some dark corner of the 'burbs where we lived, and point out the stars. The one time I've even come close to seeing the vast expanse of the galaxy we live in was on a night-time road trip to Virginia for a fencing meet, but I have never forgotten how the stars glittered in the sky--and, more to the point, how many there were.
I've always maintained a passing interest in stargazing and astronomy, but my abilities with calculus precluded me majoring in the deep spaces. Still, the night sky is not without its wonders--it's a pretty cool experience to realize that you can see Venus, that Beetlgeuse (Beatle Juice) really is red, and watch a lunar eclipse occur right before your eyes. But it was not until this weekend, when I finally bought what birdwatchers call a "spotting scope" and pointed it at the moon, that I realized, "Gee, I've got a lot of childhood to catch up on." (And no, I did not pay top-dollar for mine)
My parents, like most parents, placed a lot of value on getting good grades in school. I can't help but think that they got gypped into the belief that having an education means that you've learned a lot. I mean, I have learned a lot--but not on the things I was educated in. I've learned about proper soil composition for growing things, the names of all the major waterfowl in the Netherlands, how to feed a species-appropriate diet to cats, and which herbs to use in a tomato sauce. Amongst others. Don't get me wrong, I've also gained a lot through my education--I got my job solely because I was educated in pharmacology--but if you were to ask me which set of knowledge gives me more satisfaction in possessing, it's not the one that involves curves and data points (unless the data points are individual birds, and the curves are Gaussian distributions).
I don't claim to know the "best" way to educate kids. But I don't see how starting with their own interests could lead you too far astray. I sometimes wonder if I could have been an ornithologist, or an ecologist--given my dismal attempt to give a crap about molecular pharmacology, I wonder if I'd start feeling the same way about ecology. I don't think I would have gotten funding. I don't think I would have gotten a job. I don't think I'd be any better at writing papers. But I do think I would have learned a lot more for all my education.