Krvkurva is a group of Portuguese designers that have created the La.Ga bag.
Shaped like a large teardrop, the bag is constructed from semi-rigid Dupont™ Tyvek®. Thinner than one millimeter and weighing less than 40 grams, this bag is able to hold up to 55kg easily, while still being machine washable. With use, the bag becomes softer and more malleable, while being radiation resistant and recyclable.
Each bag is given a unique artistic layout by a different guest designer, in limited runs. Past designers have included artists and graphic designers from Spain, Portugal, Argentina, Brazil, the UK and USA.
A male version of the bag called Ga.lo (galo in portuguese meaning cock as in the male of the chicken :) also exists.
You can check truckloads of other designs here.