This unique home called Villa Vals was built directly into the hillside in Vals, Switzerland. The design is by Christian Muller Architects and SeARCH. The home is located within walking distance to the famous thermal bath of Vals. You can book a stay in Villa Vals here.
This is the winner so far. What a place for grandkids and grandnieces and nephew to come play! And a rather nice location for a coaching/art/writing studio, don't you think? (this links to a lot of houseboats)