With all due respect, why? When we have so many other things DD enjoys and that excite her (Legos, art materials, outside play, books), I can't get motivated to dig for the good stuff. I have some things bookmarked that look nice, but as yet we have found nothing that really excites her and is educational and has staying power.
My guess is that when she's older, she'll find her own challenging info online - at least that's what has evolved with our ds12. (Sorry, I can't remember how old your dd is). Our ds is *really* into Legos - he's been building things since before he could sit up (or so it seems lol!)... and eventually got into Lego robotics etc. Starting sometime last year he started looking at other people's Lego creations online. My first thought was, this isn't all that intellectually stimulating, but he spends enough time everyday studying etc, so it was ok with me to let him spend time googling Legos. This fall he asked for a Lego train set for his birthday. We almost didn't get it for him because he seemed to be getting a little old for a train set, but hey, I'm his mom and he's not going to be home for all that many more years and yep, I got him that Lego train set for his birthday. Sooooo... it wasn't long before he was online checking out other Lego train setups and suddenly he was spending all his free time contemplating the physics of trains... and I'm not talking simple physics either - I'm a phycisict by profession, and he was genuinely using a heck of a lot of brain cells on the concepts he was applying to his train set. All inspired by and benefiting from a chance to google and look at other people's creations.
He's moved on now to building a Lego robot he's going to house in a bubble, also an idea that came to him after googling. Who knows what he'll be doing next week. But whatever it is, being online seems to have helped him explore his creativity in a good way. I have an artistic bent, and I never could have developed it by living in a bubble (ie, not going to museums or looking at other art). Seeing what other people are doing, being exposed to other people's ideas, doesn't make us less, it spurs us on to think more creatively ourselves. And that's an area that I think the internet has really opened up for kids like my ds.
Anyway, I got a little off-track lol... my original point in replying was that I haven't really had to ever seek out much for my kids, they tend to find it on their own. We watch, and we have parental controls, we aren't letting them run wild online, but we've given them some freedom to roam and in return we (parents) have found a lot of cool things also
polarbear
