Elvis Costello is only 30 seconds into his set before a small audience in a Los Angeles TV studio when -- boing! -- a broken guitar string brings the music to a halt. During rehearsals, Costello has already groused about the lighting and the sound, so the tension in the wings is palpable. But the mercurial rocker calmly accepts a new guitar and starts again, launching into an acoustic rendition of Deep Dark Truthful Mirror. When Costello leaves the stage nine songs and an hour later, the audience is clamoring for more.
For the creators of Unplugged, MTV's hit program featuring...