A town accessed from the dream suite ( a feature that lets you upload a copy of your town for others to see without having them come to your actual town.) Aika is (in)famous for its "story" as you travel through the town and things become more. . . off.
In New Leaf, there's the ability to play in other people's towns through something called the Dream Suite. The Aika village was created by a Japanese player and seems to tell a story with the layout and theming of the town. It's a fun experience once you have the ability to visit there. You can also find tons of information by searching the board. (Be careful of spoilers, though.)