The Berkeley Hills Death Ride is a daunting way to get a workout. Start by riding up Marin Avenue, which can be scary in a car, let alone on a bike, given that its grade is as much as 25 percent in places. Next, hit five more of Berkeley's steepest roads: South Park Drive, Centennial Boulevard, a stretch of El Toyonal and Lomos Cantadas, and two separate sections of Claremont Avenue. (See the Web site listed above for details.) It's little wonder that few but the fittest cyclists give the ride a try. "Going up Marin is a pretty crazy thing," says Mark Miller, an Oakland cyclist who has done the ride. Mike Burns, a cyclist who recently moved from Berkeley, used the ride as a way to train for the grueling mountain passes of the Whitney Classic, a cycling event that begins below sea level in Death Valley and climbs over two 5,000-foot passes before reaching the more-than-8,300-foot elevation of Whitney Portal. "One afternoon and evening, I did two laps of the death ride," he says. "I was pretty exhausted after that." The Web site of one cyclist aptly describes such behavior as an "homage to masochism."