[ATDrake]

Originally Posted by taosaur

The Olympians comics are proving tough to find.

You can get them via Amazon (and presumably B&N) and the volumes there have the Look Inside function so that you can read a few sample pages to get a feel. The author/artist also has a fairly nifty official website for the series, and some intro/activity pages which are educational. It looks like only Zeus, Athena, Hera, and Hades are out, but apparently there are over a dozen planned.

Originally Posted by taosaur

I would still love to get some Egyptian mythology in there somewhere. I'm packing an offline wikipedia for him, but something more structured might make a better jumping-off point.

You might want to check Project Gutenberg for some older mythology-introduction books/collections of folklore/legends. They've got a couple which used to be old-school textbooks, I think, and some of them might be useful to include on the netbook if the writing doesn't seem too dry.

In paper, but highly recommended, Usborne Publishing which specializes in kids' books did have this truly hilarious series of faux-tabloid newspapers which amusingly introduced culture and history of Ancient Rome, Greece, Egypt, the European Middle Ages, the Viking Era, and Paleolithic Humans, edited by Paul Dowswell. They've been reprinted a couple of times and I think you can order the latest versions via BookDepository.com (where I got the lot a couple of years ago after envying the library copies), which sometimes offers discount coupons. Here's a link to the Amazon Look Inside version of The Egyptian Echo so you can see if they're something you or your nephew might find appealing.

And it's too bad kids don't get to learn French in US schools, since it looks like the Papyrus series of bandes dessinés aren't available in translation. ETA: just wiki-checked, and it appears that they're starting to show up in English as well. This is a rather older series which is not so serious, but the visuals are fairly grounded in historical Egyptian art and you can see a lot of representative pages at this French-language official fansite, which also has some background on the correspondence to real Egyptian places/events in the time of pharoah Merenptah, son of Rameses II.

Originally Posted by taosaur

The old Archie Ninja Turtles series was also kid-friendly and halfway educational, exposing kids to a lot of different cultures.

Fun fact: Usagi Yojimbo got its start being published by the same comicbook imprint (now defunct) that published the original Teenage Mutant Ninja Turtles (may not be the same as this Archie series you mention) and they had a crossover and UY even appeared on an episode of the TV cartoon and had an action figure.

For more 10-year-old-appropriate educational/historical comics, you might want to give a try to the following titles, which are written to be readable by both adults and older kids:

Bone Sharps, Cowboys, and Thunder Lizards and T-Minus: The Race To The Moon about the "bone-hunter wars" between pioneering early palaeontologists Edward Drinker Cope and Othniel Charles Marsh, and the Cold War space race, respectively. They both have notes and further reading suggestions in the back, and they're from GT Labs, which does science history comics and has PDF excerpts you can sample on their website. I'm pretty sure they'll appeal, as kids are supposed to love dinosaurs and rocket ships (at least, I was no exception).

Similarly, First in Space by James Vining, about the monkeys sent into orbit during the Space Race. It's written specifically for the YA market but doesn't dumb down for older readers.

Another possible Oni Press publication is Scott Chantler's excellent and recommended Northwest Passage, about the war between the French and English in Rupert's Land (pre-Confederation Canada). But that's not specifically written for kids despite the cartoony style and it's got understandable situational violence (cartoonily depicted) and a hint or two of past sexual assault in the background of one of the characters, so maybe you should read and vet it first (get the Annotated Edition, which is well worth the extra $$$) if you're interested.

You can read samples of both via Oni Press' Previews section on their website. They used to offer CBZ download previews, but no longer, it looks like.

Biologist Jay Hosler also does good science comics (a few short ones available on his website), and he's got two fun titles suitable for younger readers without being too overtly education-oriented to be a potential turnoff for a kid who's not into them. The Sandwalk Adventures features Darwin and the theory of evolution, as related in conversations between him and one of the mites who live in his eyebrow follicles, and Clan Apis is about the life-cycle of a beehive through the adventures of a honeybee.

He's also written some much more overtly use-for-teaching/learning-purposes comics, Evolution: The Story of Life on Earth, which is part of a series of graphic novels done by Macmillan's Hill and Wang college-level academic/educational imprint. It's probably a bit above your nephew's current reading level, but something to keep in mind for the future, perhaps (or just buy for yourself, which I encourage, because they're mostly really good).

Hope this helps.