Icehotel (Jukkasjärvi, Sweden)
The price tag: $145/night
Made entirely of ice and snow and designed by artists, the Icehotel in Sweden is just north of the Arctic Circle. It has both cold and warm rooms, and the hotel recommends staying in a cold room for either your first or last night, while spending the rest of your stay in a warm one. There are no bathrooms in the rooms, so be prepared to get pretty friendly with your neighbors.