The vast majority of folks who get around town on two-wheeled vehicles don't pedal about on no-name cycles -- instead, they attack the city's hills on precious $1,000 Bianchi racing bikes and titanium Cannondales that cost more than the first car you ever drove. As a consequence, San Francisco's repair shops have developed a rather nasty snobbishness about the machines they'll deign to touch, and should you drag in your disabled old Huffy or pieced-together Frankenbike, they'll furrow their brows, turn up their noses, and shoo you out unaided. But things are different at Pedal Revolution, where wise, black-fingernailed repair masters teach at-risk kids their own marketable skills while charging customers some of the lowest hourly rates in town. Best of all, no bike -- no matter how crappy -- is turned away. The mechanically inclined can also indulge in free classes and for $30 a year use all the tools in the shop. Let the good times roll.