CityPass has a 3 ($97) or 5 ($127) attraction option valid for 9 days. Options include: Space Needle, Seattle Aquarium, Chihuly Garden and Glass, Argosy Cruises Harbor Tour, Museum of Pop Culture (MoPOP), Woodland Park Zoo, Pacific Science Center, The Museum of Flight, Sky View Observatory, Seattle Art Museum.
We have plenty of things to do in and outside of Seattle. If you have the time we really recommend getting out of the city.