That Dodge Nitro sure looks like a sweet ride. Parked in an alley near Boston's Symphony Hall, it's just waiting to be boosted. My accomplice and I pull our winter caps low and sidle up to the white SUV. I pull out an electronic card, pass it along the windshield, and hear a reassuring click as the door locks release. We quickly duck into the seats, find the hidden ignition key, and start it up. No alarms. I step lightly on the gas and we pull away.

The owner of the car is fine with all this. She is Natalia Widulinski, a Northeastern University student from Stamford, Connecticut, and for $8 an hour she's allowing complete strangers to borrow her car when she doesn't need it. "I was looking for a way to pay for parking," she says. She earns as much as $300 a month — more than her $175 parking bill.