A "tidy out" collection of links (all via treehugger) about buildings!
1) Arquitectonica has won a competition to build a tower in Seville. The Puerto Triana Tower with have an "ecological core, photovoltaic cells and gray water recycling." It looks pretty funky too!
2) Jon Scroeder at Eco-Geek has gathered together a list of the top ten green skyscrapers. Of note is the Rrban Cactus in Rotterdam - if only for its quirkiness! A couple of UK entries too.
3) Treehouses! Not that I have a tree large enough to put a treehouse in, but if I did I would want this one! So pretty... It's just a pity I am afraid of heights...