There is something exhilarating about zooming down a giant slide so fast that you land — boom — on your ass. Given our current rash of innocuous swirly slides, most playgrounds don't exactly offer adults and daredevils a spontaneous whoosh of excitement or a desire to get down and dirty in the sandbox. But take heart — in the precipitous climes of Noe Valley hides one of the city's unsung treasures. Seward Slides Minipark, as it's known, is more than three decades old — a patch of green salvaged by neighborly inhabitants who wanted a fun purlieu for their kids. What most people don't know is that the park's celebrated double concrete slide was the brainchild of a 14-year-old girl named Kim Clark, who won a "Design in the Park" contest put on by sculptor Ruth Asawa. Art or idle diversion, the slides are hands-down winners, and not just because they provide hours of repetitive fun for ADD-addled kids; they offer a slick date detour for grownups, too. Groups of drunken teenagers and adults have been known to frequent the park and rocket down the slides in tandem. It's not completely a walk in the park, though; you have to watch out for glass in the sand (and make sure you discard your own refuse properly, mind you), and be chary about getting all scraped up. If you find yourself broke on a Saturday night, just bring a 40, a piece of cardboard (it makes you go faster), your rattiest clothes, and a buddy to get nostalgic with. Wheeeee!!!