Miguel Arteta's amiable Cedar Rapids is a mild comedy of embarrassment, set in the dark heart of Middle America and starring sitcom secondario Ed Helms (The Office's Andy Bernard) as Tim Lippe, a prematurely middle-aged man-child. Taking an airplane for the first time in his life, the country mouse goes to town: As the most idealistic insurance salesman in Brown River, Wisconsin, Lippe is dispatched by his dyspeptic boss to rep the company at an annual convention in Iowa's second city, Cedar Rapids. Do the bright lights bedazzle this teetotaling paradigm of cheerful repression? Not quite the 40-year-old virgin that his TV colleague Steve Carell played in 2005, Helms' nicey-nice Lippe lives out a 12-year-old's Oedipal fantasy, enjoying a weekly matinee with his old junior-high-school teacher. Still, he's naive enough to mistake the solicitation of the corn-fed hooker lurking outside Cedar Rapids' convention hotel for simple friendliness, and sufficiently lacking in savoir faire to be startled speechless upon discovering that he's bunking with a black man who appears to be even more square than he. Far worse from the standpoint of Lippe's moral code, the third roomie turns out to be the playboy of the Midwestern world: Dean "Deanzie" Ziegler (John C. Reilly). With every other joke based on Lippe's reactions or the reactions those elicit, Cedar Rapids is something of an extended workplace ensemble-com. "Welcome to the jungle, Timbo," Deanzie congratulates Lippe when the Brown River innocent realizes that not everything in Cedar Rapids is as kosher as it might seem. The insurance man's education makes for some lively farce before the obligatory cringe-inducing, Capra-worthy closer.