We have a lot of these books at home (World Records, Amazing Facts, Big Books of Whatever, Kids Almanac, etc), and both kids enjoy reading them. They also like magazines like Ask and Muse, which provide a monthly dose of fun topics.

DS10 loves Randall Munroe's What If? book, and will most likely be getting his new one, Thing Explainer, for Christmas.

Have you considered a game like Trivial Pursuit?