I have to go to Seattle for a work trip, and get to tack on a couple extra days visiting my sister and niece, who is 6yo. Of course, if the weather is nice decent, we can hang out in a park, go for a short hike or mess around on the beach somewhere. But, from the admittedly not necessarily accurate 10-day forecast, it's looking more like crappy for when I'll be there. Not being a parent myself, I am not certain what would be fun for a 6yo to do, either in the house or out and about. She particularly likes animals and science, and I think art/drawing. My sister may have ideas, but sometimes it's fun to mix it up a little, KWIM?
Any ideas for cheap or free indoor activities with a 6yo? Especially, but not limited to, the Seattle area? Or, is there a good project book for that age that might be a nice gift + useful for this?