Hi Amy. Welcome to Seattle! Which WF will you be working at? (I live across the street from the Westlake WF).
If you're interested in learning about Seattle history, the Seattle Museum of History and Industry is the place to go. It's at the edge of South Lake Union. If you enjoy walking, you can walk around the entire lake. The Seattle Center is also a great place to check out. It's free. You can ride to the top of our City's icon, the Space Needle (but they do charge for that).
Welcome yo our corer of the country Amy. This area has something for everybody. It depends on your interests and mood of the moment. The Pike Place Market and waterfront are always interesting and free. A walk on ferry ride is a pretty cheap way to see some different areas and the great Seattle skyline. The EMP has a lot of cool stuff. Lots of parks and trails in Seattle and even more in the surrounding area. Most of Seattle's neighborhoods have their own little charms, shops and scenery, so depending on where you live there may be some great things to see and do just outside your door.
Again, welcome and have fun exploring.