For a different activity, try the beginnings of four cool books. They are all old, all classics, and all terrific. Two of these great stories feature boys as heroes, and two feature girls. But everyone should enjoy all four adventures.
If you're in the car, take turns reading them out loud. Or, if you're on a plane or a train, read them to yourself. It can be fun to try them out — and, if you like them, you can read the rest later. These stories are a lot older than Harry Potter or American Girls, and exciting in a different way!
If enough people in the family love the book, just stop at a bookstore in the next town or city. Since these stories are classics, most bookstores will probably have paperback copies, which aren't very expensive. Then you can read a couple of chapters a day.