And to think I used to live next to this place.

My favorite named theme park is in Gifu Prefecture, and is located about 20 minutes drive from where I used to live. It's called The Site of Reversible Destiny in Yoro Park. Much to my chagrin, I never actually went here because I was afraid of changing my destiny. Things were going ok (although perhaps some of my friends will tell you otherwise) and were very interesting, but it looks like I really missed out. The park's focus is an experience of the unexpected that will "give you many opportunities to rethink your physical and spiritual orientation to the world." Other features include the Critical Resemblance House and Trajectory Membrane Gate. There are some interesting photos of it on Flickr as well