The Nike Women's Marathon starts in Union Square, winds through Golden Gate Park, and ends up at the Pacific Ocean. With nearly 20,000 men and women taking part, the energy is electric, the volunteers organized and ubiquitous. DJs and bands jam along the route, and there are multiple stations serving up water, Gatorade, energy bars, and even Ghirardelli chocolates. Finishers are handed Tiffany necklaces by tuxedo-clad porters. The race, now in its seventh year, is so popular that participants must register by random drawing. This year's race is on Oct. 17; fees are $115 for the half marathon, $135 for the full. So sign up, lace up, and get to that finish line: Your reward is waiting.