After dark sizzles in San Diego with fancy dance clubs and nightspots, cultural happenings, casino action, and bars galore -- from beach bars to piano bars, sports bars, dive bars, and just plain neighborhood bars. Weekends are especially hot. Most cultural happenings -- symphony, theater, and opera – unfold downtown. Coffeehouse culture, with music at night, is also big. At the nearby Gaslamp Quarter, martini bars and upscale dance clubs abound, including the three-story Stingaree restaurant and nightclub with waterfalls and translucent floating staircases leading to a rooftop bar. Dance clubs and bars of Pacific Beach and Mission Beach attract a more casual, typically younger crowd. Bikers hang out at Ocean Beach to soak up reggae and Grateful Dead-style jam bands