Tenacious D took on Virgin Records in Union Square (where rumors have been flying that it too, like Tower Records in the Village, might also be closing) in an in-store appearance in support of their latest film and soundtrack release The Pick Of Destiny. Entering the record store like two stoners raised on Big Macs and Bud, Jack Black, who recently starred in King Kong and Nacho Libre, and Kyle Gass goofed with the photogs up front that were preening and posing like centerfold models for Playgirl mag in their oversized t-shirts and jeans. Signing for the 300-plus people, the dynamic duo shook hands, posed for pix and made a playful nuisance of themselves as they promoted their new flick, an appearance on the Letterman show and a date at the Garden last week.