We are no newcomers to the San Francisco cab experience — near accidents, accidents, swearing in a multitude of languages, and strangely heartfelt drunken conversations with Yodalike drivers — but placing a disco ball and flashing lights, timed to a thumping Arabic beat, in the backseat does stir the pot. Meet Disco Cab, the work of Haydar Alhakim, who makes a typical crosstown trip into something of a party. Why spend your ride babbling at the driver or checking your e-mail when there's a dance dance revolution to be had? Disco Cab isn't a more expensive transportation experience, just a richer one.