Jonathan Barnes’ Ultimate Taxi sports a topflight sound system, a disco ball, laser beams, and a fog machine. And just when passengers think they’ve seen it all, their Pink Floyd-crooning driver reaches over to the front passenger seat of his “nightclub on wheels” and reveals the quintessential ‘90s accessory: a laptop attached to a digital camera and a cellular modem. A few clicks later, his fare are staring at their digitized faces on the screen. The next day they can view their mugs on Barnes’s Web site: http://www.ultimatetaxi.com.

    “I built the car to take me on an adventure,” says the 38-year-old Aspen Colo., hack, who has logged more than 350,000 miles in the Checker since he bought it in 1985. Early amenities included a telescope (to show fares “the moons of Jupiter”) and a small television. These days the multi-tasking Barnes steers with his left hand and works his synthesizer, saxophone and computer keyboard with his right, as Web surfers bombard him with email comments and jokes to share with passengers. Among the celebrity visitors who have forked over a premium $20 per person for 20 minutes of mobile sensory overload are Pierce Bosnan, Jerry Seinfeld and Lee Iacocca.

    “I drive very slowly, because safety is my main concern,” says Barnes, who claims he’s never had an accident and maintains that he always pulls over to the side of the road to answer email. Still, he quips, multimedia cabbies, “need to be on a first-name basis with all the police in town. And have an insurance company that has never exactly ridden in your car.”