In the new flick “You, Me, and Dupree,” the shaggy haired blond and one-time indie movie icon Owen Wilson stars as a charming yet frustrating man-child with a Zen-like heart. Down on his luck, this free spirit imposes himself on his best friend, Carl (Matt Dillon), and his new wife, Molly (Kate Hudson), prompting all manner of alleged hilarity. Will devil-may-care Dupree loosen the uptight newlyweds? The question is answered, of course, but by the time the credits roll, the film feels like the two-hour pilot of an average half-hour sitcom.

Last summer’s surprise comedic hit “Wedding Crashers” was the high-water mark for the genre best described as “forever frat,” a milieu that features any combination of Adam Sandler, Will Ferrell, Vince Vaughn, Ben Stiller, and Mr. Wilson as post-adolescents learning how to grow up while still holding on to the bad habits of their youth. Other examples of this breed include “Old School,” “Dodgeball,” and the recent Sandler epic, “Click.” “You, Me and Dupree,” while a steadfast part of this historic artistic movement, tries to be more than just puerile jokes celebrating the emotionally stunted. It struggles to put forth a sentimental moral about preserving one’s individuality while embracing the normal customs of maturation. But in the end, it’s nothing more than must-see television, a wacky skit stretched thin.

“You, Me and Dupree” begins with Carl and Molly settling into newlywed bliss. But unfortunately for them, their fantasies of “happily ever after” are denied when Dupree moves in for a few days, which turns into weeks. Soon, the tightly wound couple is sneering, rolling eyes, or freaking out at Dupree’s antics — he sleeps in the buff, backs up the toilet, and conjures riots of manliness in the pristine house. Of course, Carl is torn between his collegiate glory days and the serious responsibilities of adulthood. On top of that, Carl is employed by Molly’s father; a wealthy and intimidating captain of industry who seems determined to sabotage his daughter’s marriage. Played by Michael Douglas (a bit of a surprise, to say the least), Molly’s father is a bitter, mean-spirited land developer. Mr. Douglas, an expert at appealing scumbags, is the nightmare father-in-law, a domineering jerk who makes good in the end. As Molly, Ms. Hudson is more radiant than usual, and the best compliment I can offer her is that this movie is too small and simple for one so talented and beguiling. She more than holds her own against the dudes she’s cast against.

The flick is sketch after sketch of Dupree innocently spreading chaos throughout conformist suburbia, and at times he reminded me of a low-rent Chauncey Gardiner, the seemingly developmentally challenged messiah character played by Peter Sellers in Hal Ashby’s classic film “Being There.” But alas, the only real similarities between the two are the actors’ eyes, which brim with wonder and confusion. As the movie inches along, milking what can be milked from a movie that spends two-thirds of its running time inside a small house, Dupree slowly changes. His annoying ticks and excesses prove themselves to be an idiosyncratic front for a poetry-writing Buddha who can save marriages, reconcile in-laws, and force people to believe in themselves. Well done, Dupree!

Mr. Wilson’s career arc reflects the title character of Randy Dupree, lovable flake, eternal teenager. He has the makings of an excellent comic actor, preferring subtle expressions and line-readings that could enliven more grown-up fare. Instead, Mr. Wilson’s talents seem to have been flash-frozen somewhere in the 1990s. The laid-back intelligence and wit he exhibited in Wes Anderson’s indie classic “Bottle Rocket” have been institutionalized and caricatured. He’s now just a clown, a ramblin’ man with a surfer’s tenor who’s part loser, part savior. While this works for a comedian like Mr. Vaughn, it seems a waste of Mr. Wilson’s talent. I’m not suggesting he immediately become a stodgy, serious actor, but surely Mr. Wilson could command smarter scripts.

“You, Me and Dupree” strives to find a compromise between Dupree’s roguishness and Carl’s common sense. The film suggests a turning point for a genre that revels in flatulence jokes, regards stunted post-adolescence as a subversive statement against the establishment, and tries to reflect the changing definition of what it means to be an adult. Such a change seems necessary, as the audience for this genre is simultaneously getting younger and older. To those under 25, these overgrown “big man on campus” flicks must seem filled with dudes who are, well, old. And to those over 30, the dudes in these flicks look our age, but act younger than 25 … which is increasingly, well, pathetic.

“You, Me and Dupree” provides emotional training wheels to help the stunted adolescent maneuver from “Old School” to more considered fare, perhaps “The Lake House.” If movies like this continue apace, I can’t wait until the artists involved and the audience grow into middle age, which might well be 60 years old.