Old School fans, remove your earmuffs: This messy, raunchy farce about three groomsmen (Bradley Cooper, Ed Helms, Zach Galifianakis) on a lost-weekend bender in Sin City is just as uneven but almost as funny, continuing director Todd Phillipss fascination with the alpha males default settingchildhood reversion. To put it another way: This is a movie about three yutzes who wake up face-down in a high rollers suite with live chickens, a smoldering armchair, and a Jacuzzi full of inflatable livestock. At that point, they must answer the burning question: Dude, wheres my groom? As their search leads from cut-rate wedding chapel to no-tell motel, the Jon Lucas and Scott Moore screenplay strives mightily to strew banana peels in their pathmost amusing, some merely desperate. What proves consistent, as in Old School, is the chemistry among Hangovers three species of party mammalia: Cooper has the smarmy look of an avocational gynecologist; Helms uses his wall-mounted Whiffenpoof features to manic effect, with a girlish shriek for each new catastrophe; and the ursine Galifianakis, a master at detonating sicko one-liners with a slow fuse, adopts a gut-forward toddle and an air of guileless hedonism. Together, they form a lopsided portrait of flabby, shabby wannabe machismoan instant rejoinder to the old taunt man up.