Visit Chateau Ste. Michelle Winery
It is about 15 miles north of Seattle in Woodinville. It is absolutely beautiful there and tons of fun to visit. They have wines for sale that you can only get at the chateau. They also have concerts and special dinners that are a nice treat. When I lived in Seattle the Bellevue Rep. Group used to do Shakespear in the grass at the Chateau every Thursday night. It is one of my favorite summer memories. Columbia Winery and RedHook Brewery are close by as well.
Visit Snoqualmie Falls
You can hike up to the falls or putt around in town (where Twin Peaks was filmed). The falls are gorgeous and it's only a one mile hike. The Salish Lodge is gorgeous if you can get in for dinner.
Visit Bridle Trails Park
I used to live on this park just outside Bellevue. It is so pretty at this time of year (although you may want to take allergy medicine before you go if you suffer from environmental allergies). You can rent horses nearby and ride on the horse trails in the park.
Visit Pacific Place for Great Shopping
Definitely the best shopping in Seattle. Pike Place market is the coolest open market with neat vendors, as mentioned above. I would check it out as well.
If you want more info let me know!
Laura