Try eating inside an igloo!
Unfortunately I didn't take any pictures but Kumakura means igloo and this restaurant, once you enter is about 1/2 are little rooms the shape of small igloos you have to crawl inside. Otherwise the other spaces are almost like tree houses meaning imagine a small kind of house you see in some movies as tree houses. The rooms are too small to stand in but there's just something cool about it all like your a kid again or if you are there with your girlfriend then it's all just very playful.
The food wasn't bad either. Kind of new Japanese style.
As it's pretty small and fairly popular you will need reservations so call ahead.
There are a few pictures here.