t's 2 a.m. in Aspen, and somewhere among the mirrored disco ball, the laser lights, the keyboard, and the speakers blasting music, cabbie Jonathan Barnes manages to find the steering wheel of his multitasking hack. In his Ultimate Taxi, Barnes does a full song-and-dance performance while driving his clients around the streets of Aspen.

But there's more to this yellow taxi than a rolling discotheque. Amid all the lights and musical instruments filling the front of the cab is a laptop computer, which is hooked to the Web via a cellular modem.

"My next step will be to take live pictures of the people in my cab and send them up to my home page," says Barnes. "Imagine watching a live picture of yourself on a Web page while you're being entertained as you cruise the streets of Aspen. I'm billing it as the first lightspeed taxi ride."