Kids Web Japan, especially the Virtual Culture portion, is a site designed specifically to help kids learn about Japan! This page has the culture links pretty well covered; if you're looking for anything on culture, I'd wager you can find it. Activity Village also has a fun page on Japanese culture for kids, as well as some crafts. Here are more crafts from Enchanted Learning, and some from the Crafty Classroom. DLTK Kids also had some fun links, like counting to ten in Japanese and other interesting crafts (although the karate kid made out of a toilet-paper roll may not count as "preserved Japanese culture"). I like the coffee-filter fan and the Dessert Sushi here.
Comm. Central mom Jennifer Sathianathan is running with the Activity Book's idea of a Japanese meal, complete with rice with chopsticks, fish (sticks), and tea, followed by a round of sumo wrestling! How fun is that?!
(Note: I told Jenn I would need to tell all you moms about the pool-noodle-and-duct-tape light sabers she fabulously constructed, like these--but somehow, I cannot find a true link to history. So Yoda and a dotted line to Japan are about as close as I will get, just in time for pool noodle clearance sales.)