First, there was the Ice Hotel, located in Jukkasjärvi, which saw the world's first ice hotel, in 1989. Pretty cool, eh? I suppose that's supposed to be taken in the literal sense of the word. You can actually book a room through their website here.
Then, I found another wacko hotel in Sweden, and that is the Jumbohostel. People have converted a Boeing 747 and parked it near the Stockholm Arlanda Airport, and transformed the interior into dorm rooms, private rooms, and even a cockpit suite. There's also a restaurant and a lounge inside. And yes, you can book a room through their website here.
Wow. I have to say though, that even if I enjoy weird things like these, I do not suppose this would be reason enough for me to take a trip to Sweden. I need more than that. After all, when I travel, I don't spend a lot of time in hotels, I spend my time outdoors.