Two passes to Seattle's Museum of History and Industry: MOHAI! As described by the museum itself:

Explore the history of Seattle and the Puget Sound Region. MOHAI is respected nationally and treasured locally as a dynamic, innovative museum where historical exploration inspires people to create a better future for themselves and their communities.

With changing exhibits, a zone just for kids, and a spectacular location on the water, a trip to MOHAI is fun for the entire family.