Farmers work long hours under the open sky, struggling to finish each day's planting, cultivating, pruning or picking before the sun sets. It's hard sometimes to imagine, while engaged in this day-to-day pressure, but city people often welcome the chance to pay for an hour or two on that farm, especially if they can pick their own fresh fruit or vegetables. For many urban people, just getting out of town to a farm is a delicious pleasure. The University of California Sustainable Agriculture......