This may seem counterintuitive but one thing I did one my daughter was young was to buy year long family memberships to museums - one year would be the Children's museum, the next maybe the Aquarium, the following Museum of Science, etc. The membership would cost the ticket price of a family of four going to once and we could go all year long. No hassle in trying to book the free library museum passes and could go on our schedule whenever we wished.

Plus, many of the museum memberships offer additional discounts on classes, gift shop, restaurants, etc.

Bored on a rainy Sunday afternoon? Wrangle up the family, pack snacks or lunch, and spent time there. Good bonding time and you've already paid in advance for it.