Bike rides for all experience and stamina levels on this day of riding through Carroll, Patterson, Herring Run and Druid Hill parks. So enjoy a leisurely 12-mile ride, or test your speed and endurance with a more intense ride, like the 64-mile "metric century." And once you're done, there's a barbecue! All proceeds go to the city's parks, environmental and cycling groups, so don some spandex and your two-wheeled steed and get riding.