Traditional bike racks are so boring that I often forgo their use for more extreme locales, like power lines or roof decks or strapped to the backs of random passersby. In that vein I would probably use this concept, which would see my bike suspended from the side of a building.
Called Bike Hanger, this proposal is the brainchild of New York's Manifesto Architecture. Riders attach their bikes to the lift, and presto, it's lifted into the air much like those crazy Japanese car elevator/garage combos we've seen plenty of times before.
There's a catch, however, and it's a labour-intensive one. To get your bike up and at 'em, you see, you'll need to get on the nearby stationary bike and pedal that sucker up into the sky. That eliminates the power requirement, making this one lean green pedalling bike rack machine. [Fast.co Design]