"Welcome Home Roscoe Jenkins" is a happy surprise of a movie, a heartfelt comedy that probably shouldn't work, but does. Seemingly the entire plot and nearly every scene has been cobbled together out of the spare parts of other films—i.e. "The Family Stone," "Meet the Parents," "Dan in Real Life," "Wedding Crashers," "Guess Who," etc.—and the story's outcome is a prime example of foregone predictability. Suffice it to say, originality is not its strong suit. And yet, writer-director Malcolm D. Lee (2005's "Roll Bounce") treats the material with affection and respect, cooking up occasional big laughs while selling a nostalgic sentimentality that actually seems like it comes from an honest place.

To help celebrate his parents' (James Earl Jones, Margaret Avery) fiftieth wedding anniversary, successful Los Angeles talk show host Dr. RJ Stevens (Martin Lawrence), young son Jamaal (Damani Roberts) and "Survivor" winner-cum-girlfriend Bianca (Joy Bryant) travel to his small hometown in Georgia. RJ—short for his real name of, yes, you guessed it, Roscoe Jenkins—has been gone for nine long years, and is looking forward to reacquainting himself with his mom and dad, brother Otis (Michael Clarke Duncan), sister Betty (Mo'Nique) and cousin Reggie (Mike Epps). In an instant, his childhood feelings of jealousy and resentment reemerge with the appearance of competitive cousin Clyde (Cedric the Entertainer) and teenage crush Lucinda (Nicole Ari Parker), who was stolen from him by Clyde over twenty years ago.

Would it have hurt to add a comma to the title of "Welcome Home Roscoe Jenkins?" Grammatical error aside, the picture takes about twenty minutes to find its footing and then slowly grows on the viewer's soft side. The trajectory of the story is obvious before the halfway point, but the writing is nonetheless sly and raucous, and the one-liners are pulled off by a game cast of comedic talents. The Jenkins family's continual mispronunciation of Bianca's name is very funny, as are all of the characters' quick-witted dialogue exchanges. A raunchy bit, thought to be old-hat, involving the sexcapades of two dogs is even made kind of fresh by the bawdy way in which it is presented, pushing the boundaries of an already hard-edged PG-13 rating. With these successes ultimately come some over-the-top scenes that fall flat—a messy kitchen fight between RJ and Clyde is simply irritating—but they are fortunately over and done with quickly enough.

The more dramatic moments near the end, with RJ and his father having a falling out over some unhealed wounds from the former's younger years, are plodding but not as sappy as they could have been in lesser hands. It also takes RJ a little too long to see Bianca's arrogant true colors, but that's to be expected for the feel-good finale to work. Overall, the film has a laid-back feel that, even when being broad, is naturalistic to the way families treat each other. There's a hint of dysfunction, to be sure, but there is also love, and when the chips are down, they think nothing of standing up for one another.

Martin Lawrence (2007's "Wild Hogs") is an amiable fit for RJ, stubborn yet sweet, and at least he is capable of doing more than scowling like Ice Cube does in every movie. Though he is the lead star, it is the supporting cast who go beyond the call of duty. Mo'Nique (2006's "Phat Girlz") is a firecracker as the brazen, uninhibited Betty, and gets a great deal of the laughs. She knows how to sell her dialogue for maximum comic effect. The same goes for Joy Bryant (2006's "Bobby"), who takes the potentially thankless role of the snotty girlfriend who is all wrong for RJ and turns her into a character who goes a little deeper than the usual stereotype. Bryant has big fun with the role, refusing to make Bianca insufferable to watch. As matriarch and patriarch of the Jenkins clan, Margaret Avery and a welcome James Earl Jones are comforting presences, level-headed amidst the chaos. And as love interest Lucinda, Nicole Ari Parker (2005's "King's Ransom") is radiant, finally getting a juicier part than she is accustomed to. Of the major players, Cedric the Entertainer (2007's "Code Name: The Cleaner") is the weak link, less because of the actor than because his character of Clyde doesn't have a whole lot to do before the third act.

"Welcome Home Roscoe Jenkins" is warm and inviting, madcap and still sweet. At a lengthy 110 minutes, the time goes by in a flash thanks to the entertaining charisma of the performances and capable, brisk direction by Malcolm D. Lee. The music is well-chosen, too, complimenting scenes rather than just a collection of present-day, flash-in-the-pan Top 40 songs. Will "Welcome Home Roscoe Jenkins" change the world? No. Is it unfailingly clear where the plot is headed? God, yes. The key to success is how well the tried-and-true subject matter is handled, and that's where it gets things right. The film may not be innovative, but it mixes heart with a laudable sense of playfulness in just the right measure.