When I first saw This Is Spinal Tap in high school, I thought it was an actual documentary. Seeing it again today, I cringe at the obliviousness of my youth. A record label head named Sir Eaton-Hogg? A song called Sex Farm Woman? An album called Smell the Glove? Dana Carvey and Billy Crystal as mime waiters? Paul Shaffer as an inept Midwestern promoter? Howard Hessman as a big-shot band manager? Fran Drescher cast as something other than the most annoying woman on the planet? The clues were all there, staring me right in the faceand yet I still believed. Why? Simple: The members of Tap, expertly played by Waiting for Guffman and Best In Show comic laureates Christoper Guest, Michael McKean, and Harry Shearer, were utterly credible as big-haired, age-of-excess Brit rockers. Now, stripped of their garish costumes, theyre touring unwigged and unplugged behind the tunes produced by Tap and the Folksmen from 2003s A Mighty Wind. Given the acoustic setup, theyre unlikely to crank it up to eleven. But what theyre sure to deliver is peerless stage banter interspersed with surprisingly competent musicianship. All ages.