Gaelic Storm likes to throw a little improvisation into its shows. But Gaelic Storm, an Irish music phenomenon for the past several years, isn't an improv band -- a small hitch in the plan that neither the musicians nor their audiences seem to mind. "We frequently build sections into our music where we don't know what's going to happen," said band member Steve Twigger. "We play the same songs night after night, but they're never the same twice." But spontaneity can be tricky on stage, he admitted. "They frequently go nowhere. And those are the fun ones," he said. "That happened recently and we literally had to stop in the middle. We just burst out laughing. The audience realized it wasn't a master class in virtuosity ... but we were there to have a good time." Twigger, from Coventry, England, sings and plays guitar, bouzouki and mandolin with the popular band.