You don't have to make extreme efforts like tying yourself to a tree to help the environment these days, even if it is definitely the best way to meet girls who're also tied to the tree. To get chummy with the earth with just a simple bag, check out Cyclus.
Born of an industrial design thesis project on reuse, Cyclus fashions distinctly sharp-looking waterproof backpacks, messenger bags, briefcases, and wallets exclusively out of used inner tubes from Colombia, because they're based there, not because helping the environment would actually be a brilliant cover for a smuggling operation. No it wouldn't. The fun begins with an array of messengers that're all pretty much laptop-sized, but rock a variety of rubber textures and designs: the Chapatin gets visible inner tube striations, a flap with two big snap buttons and an adjustable seat belt shoulder strap; the Plaza T 2010's made of smooth rubber and has a Velcro flap and mesh pockets inside; and the Voltio's got a subtle cobblestone texture and truly unique closures made from an electrical plug and outlet -- more likely to turn you on than one day turn on you. For backpacks, there's the Caparazon, in a clean cube-ish shape with pockets on top of pockets, all layered to hold a 15-inch laptop and an assortment of electronics, batteries, and cables, and the Dragon, with pockets sized for notebooks, pens, MP3 players, and cell phones, and with a segmented outer shell that, when pulled up into its closed position, creates a half-globe that makes you look a bit like a turtle, which will make everyone want to flip you over on your back, poke you with sticks, and then go wash their hands.
Cyclus also creates durable rubber wallets, including a small one with a slick surface and plentiful credit/business card pockets; and one called the Billeplana, with loads of pockets, including a secret one -- where you can stash your pocketknife for when you realize all those tree-lashed chicks are also committed to extreme not-showering.