Pop eats itself with gusto, but it’s a meal only partially digested in this amiably rambling documentary on Harry Potter fandom. Director Josh Koury piles a bit of everything onto our plate, from riffing on the Potter mythos to describing tribute bands that proliferate like crazy while generating legions of fans all their own. The bulk of the movie is given over to the musicians, an engagingly geeky cross-section ranging from seven-year-old hellions to aging Gen-X-ers with kids of their own, who expound on the glories of the boy wizard or pound out Potter-obsessed power-pop (loosely modeled after the sweetly naive anthems of Jonathan Richman). Much of the music is surprisingly clever and the players’ enthusiasm is infectious, but the film lacks focus and often sacrifices depth for breadth, flitting from fans butting heads with intellectual copyright issues to Christian fundamentalists being miffed at J.K. Rowling’s “glorification” of witchcraft. (At one point, there’s even a brief but jarring turn toward melodrama as a young fan describes her battle with a life-threatening illness.) Ignore the scattershot approach, however, and there’s considerable pleasure to be had in spending time with these bizarre enthusiasts and watching the creative ways they find to express their obsessions. Even if the Potter books don’t represent the “great time in literary history” claimed by one of the movie’s more hyperbolic interviewees, We Are Wizards is nothing if not an amusing reminder that Rowling’s creation remains an absurdly malleable source of inspiration.