In the world of interior design there is really nothing so revered as the chair.  Whenever there is a design retrospective, a clever contest, or a new furniture line released, you can bet a chair is front and center.   The requirements for being a chair are pretty basic.  All you need are a horizontal surface to rest your bum, and a vertical surface to lean back against.  Voila!  You have chair.

It should be no surprise then that sustainable design has given birth to a host of chairs of all shapes, sizes and materials.  Although most are fairly mainstream in style,  some take an entirely different approach, creating unique and fun seating out of unexpected materials.

via Hugh Hayden Design

Tennis anyone?  Created by Hugh Hayden Design from re-purposed, used indoor court tennis balls, this chair is just plain fun.

via Boris Bally

This dynamic, colorful chair is created by Boris Bally from re-used street signs.  Champagne corks form the padded feet.  Let’s see… four legs at one cork per leg equals… four bottles of champagne per chair.  Bet those are fun chairs to make!

via Voos Furniture

Of course, if you really want to get into used corks, look no farther than the 100% recycled cork  Tilter chair from Voos Furniture.   By utilizing small cutouts at the base of the backrest, the Tilter is able to tilt and spring, providing additional comfort to the sitter.

via Grain

Grain’s Cafe America chair may not look that comfortable, but the makers swear that all that used chain link fence cradles your tush in metal mesh coziness.  Whether it does or not, kudos to Grain for designing their chair with removable spacers, thus enabling it to be shipped flat pack, as well as easily stored.

via Osian Batyka-Williams

Constructed of discarded restaurant flatware, the Cutlery Chair by Osian Batyka-Williams looks the love child of Frank Gehry and a food fight.

via Bike Furniture

How cool is this chair made almost entirely from repurposed bicycle parts?  Especially when you add in the flame motif?!  The best part of all though is that old -fashioned horn on the side.  Can’t you just picture lazing back in this chair, giving that horn a honk and yelling “Honey – would you get me another cocktail please”?

via Studio Lo Design

And last, but certainly not least, we have the Pano Chair which has taken the efficient use of material very seriously, with beautiful results.  Designed in France by Studio Lo Design and cut from a single piece of plywood, this chair is put together like a 3D puzzle, without the use of nails, screws or glue.   Truly a singular approach to the common problem of how to keep things simple and sustainable. Personally, I think Ikea should try to get Studio Lo to replicate this for them.  Talk about your ultimate flat pack!