Consider permission permanently granted to be outlandish: other towns may surprise you, but in San Francisco you will surprise yourself. Good times and social revolutions tend to start here, from manic gold rushes to blissful hippie be-ins. If there's a skateboard move yet to be busted, a technology still unimagined, a poem left unspoken or a green scheme untested, chances are it's about to happen here. Yes, right now. This town has lost almost everything in earthquakes and dot-com gambles, but never its nerve.