Crop Mobbing

"The Crop Mob, a monthly word-of-mouth (and -Web) event in which landless farmers and the agricurious descend on a farm for an afternoon, has taken its traveling work party to 15 small, sustainable farms. Together, volunteers have contributed more than 2,000 person-hours, doing tasks like mulching, building greenhouses and pulling rocks out of fields."more
http://www.nytimes.com/2010/02/28/magazine/28food-t-000.html