LOS ANGELES, July 3 (UPI) -- This Is Spinal Tap , returning to theaters Saturday, has given society catchphrases like "turn it up to 11." Revisiting the comedy ahead of its forthcoming sequel shows there is much more to it than the most memorable parts, such as going to 11 or dead drummers. Spinal Tap is a documentary satire following Marty DiBergi (Rob Reiner), a filmmaker documenting the heavy metal band Spinal Tap. David St. Hubbins (Michael McKean), Nigel Tufnel (Christopher Guest) and