Kayu Kayu Ac Park is one of the newest parks in the Seattle area, having been renamed and dedicated in June. I stumbled upon a local blog article on the occasion. This park is amazing, mostly because of it's perfect location next to Puget Sound.
Location: 19911 Richmond Beach Drive NW, in Shoreline.
Number of swings: 2 regular, 2 baby
Ground material: Wood chips
Chain length: Medium.
I really love this park. It's newer, so everything is still mostly unspoiled. The swings aren't the best as far as chain length, but you can look out over the Sound, and that's something I consider a trump card. All that separates this park from the water is the railroad tracks, so some well-timed swinging can be accompanied with locomotion sights and sounds.
How to get there: Bus route #348 stops on somewhat-nearby 24th Ave NW.