Gregg Fleishman is an amazing artist designer and inventor from Culver City CA. I came across his furniture on flickr (check out these two amazing pieces). Gregg is focused on making building simple. Each piece of furniture is made of only one piece of board. The piece is composed by Origami-like folding.
Gregg also offers garden structures that are beautiful and easy to build (see here for a video). But I found the Playgoda to be the most impressive. The ultimate flat-pack.