Mostly campsites, of course.
There was the time my dad and I slept on the grounds of a ten million dollar summer vacation farm on an island in the Puget Sound. The (presumably) incredibly wealthy owners weren't home, so we got some water from a spigot on their beautiful farmhouse (what a view of the Strait!) and bedded down behind the nicest garage I have ever laid eyes on: massive, and entirely constructed of redwood slats. Woke up early the next morning and rode straight to town for breakfast.
On that same trip we slept in a hundred year old artillery sighting bunker on a different island.
A buddy and I spent the night on top of Hurricane Ridge in Olympic National Park. Woke up looking down on the clouds.
Recently I slept in the outdoor eating area of a bar in a nothing-town (a collection ill-kept farmhouses and a bar) in the hills outside of Centralia, WA. Thankfully, the bar was closed for the season -- lord knows what kind of people drink there.