Attending an Aimee Mann show is no different than flipping a coin. Some nights she's on -- clouds part, angels sing and souls are saved -- and others, well, you're left scratching your head as to why you didn't just order Thai takeout instead. Let's hope the recent release of The Forgotten Arm will provide the spark that the melancholic singer-songwriter apparently needs. Five years after her songs inspired director P.T. Anderson's Magnolia, Mann revisits that terrain with the soundtrack to Arm -- except, of course, that the latter film was never released or even produced, and pretty much exists only in Mann's mind. The concept album/"soundtrack" tells the story of a carnival worker who falls for a down-on-his-luck boxer and loses it all to the heroin addiction he acquired in Vietnam. Recorded in "live" takes, its cinema-flavored songs fit perfectly into Mann's live show, packing the same kind of emotional oomph as Magnolia's crowd-pleasing "Save Me."