If you're looking for a day in Seattle, here are some fun example for itineraries. You could spend the day sightseeing and museum hopping, or you could have a day of viewing the nature and beautiful views that are within the city.
If you're looking to stay on the "Eastside" (Redmond, Kirkland, Bellevue), then this itinerary is for you! Spend the day in Redmond near the hotel. Stop at the Saturday market inside the Town center, walk through the beautiful parks nearby, and then play some mini golf!
Or, spend the day in Kirkland at the waterfront! Hannah was born and raised in Kirkland and spent a lot of summers at Houghton Beach. Shaydon and Hannah love to have picnics at the various beaches around Lake Washington.
Here are some lists of recommended things to do in Seattle and on the Eastside. Note that there are lists of more kid-friendly, family things, as well as separate lists for more adult-oriented activities.