Book Igloo sculptural installation by Colombian artist Miler Lagos at MagnanMetz Gallery. This probably wouldn't be so practical for the home, actually, but wouldn't that be the best fort ever? (This is colossal + nevver)
Awesome kid fort idea: king size duvet cover plus exhaust fan facing into duvet cover=awesome fort. Or use a king size bottom sheet over a queen size bed and face fan inwards. Great hot summer night idea for kiddos.