Photographer Michael Wolf has documented something as unusual chairs on his travels in China, or as he calls them: Bastard Chairs.
I am rather keen on making something like this tree-trunk chair for a future DIY project. I originally wanted to create a chair from a root, by I believe it will be easier to find somethinglike this:
But do check out his pictures for more interesting gems like this office chair with a home made foot created with a bucket and sement.