Stumbled on this website today.
It chronicles a family building an octagon house.
There's a floor plan, although they exclude the basement. (I wish they hadn't. Having grown up in CA I've only ever seen on house with a basement, and it was pretty creepy/disgusting. I'd like to see what they did with theirs, though.) There are tons of pictures. The guy did a journal of building it.
The whole thing's just fascinating and turns out quite lovely in the end.
I think I'd like to live in a house like that when I grow up.