Starting July 21st ZipCar dares you not to drive. CoolHunting reports that the company has introduced a new program: the Low-Car Diet. For those willing to take the leap and go car-free for a full 30 days, they are replacing "participants' car keys with a complimentary transit pass, a free one-year Zipcar membership, drive time credit and a number of other perks from local partners. In the New York City area, Zoo York will aid......