Apart from their tendency to burst when stabbed with glass whilst inflated to 120psi (over 8-atmospheres), bicycle inner-tubes are otherwise almost indestructible. At the same time, they're very easy to cut and sew and otherwise shape to your favorite design.
Wikkerink Design has taken a stack of old tubes and fashioned them into billfolds and wallets of various shapes, along with belts and credit-card holders. Combined with felt and fabric sections, these look like they would last you forever, and as the rubber is a natural material they should age gracefully, like leather or Sean Connery.
Worried about that old-rubber smell? Don't be. I have made a lot of things from old inner-tubes and while they do smell at first, the rubber aroma wears off surprisingly fast. Wikkerink's wallets start at $21, and are apparently treated so they feel like velvet.
Wikkerink Wallets [Wikkerink via Pedal Consumption]
