You all know that I'm a sucker for flat-packed furniture. Ronen Kadushin has taken this further by sharing his Hack chair through a Creative Commons License. Ronen says he was inspired by the Open Source software model. So, if you love this and have access to a laser cutter or CNC, you can download the files to make your own. It's made from a single sheet of metal, with nothing but a few clever origami folds required to pop it into chair form.
The design is aggressive and angular, and it may not be your style, but I love the concept of open source design.
Images from Ronen Kadushin. Thanks to Dezeen for the tip.