Following an amusing supporting turn in the minimum-wage comedy Waiting, Dane Cook takes the lead in this similarly silly cinematic concoction, which sees his character Zack barely working at a Costco-type warehouse store. Was Ryan Reynolds not available? As a lead, Cook lacks any significant character traits beyond his groomed designer stubble; far more interesting is his archenemy Vince (Dax Shepard), a petty, egomaniacal cashier who has nonetheless created a minor fiefdom around his swift checkout skills. Efren Ramirez, Harland Williams, and Andy Dick round out the cast, though any one of them should have switched roles with Cook, who is a more natural comic jerk than a sympathetic or romantic figure. Don Calame and Chris Conroy’s script is witty and peppered with good laughs, but cops out a bit at the end with an overly conventional resolution. As for Jessica Simpson . . . her character is virtually irrelevant, as is her acting ability.