2010 vintage house built with sloping floors, intentionally.
See:
http://www.nytimes.com/2010/08/12/greathomesanddestinations/12location.html?_r=1&hpw
(We live with that, too, in 1882 Odd Fellows Putney building. On top floor where the footing is challenging. Old plank floorboards, carpeted over, offer slopes.
We bees cool, too.......)