"A Guy Thing," directed by Chris Koch (2000's "Snow Day"), benefits from being released only one week after "Just Married." Both films are romantic comedies targeting the teen and twentysomething demographic, but the difference in quality is telling when they are placed side by side. While much of the humor in "Just Married" seemed tired and fell flat, and the meanspirited script made way for a central relationship not worth caring about, "A Guy Thing" flows more smoothly on all counts.

The screenplay, extraneously credited to four writers (Greg Glienna, Pete Schwaba, Matt Tarses, and Bill Wrubel), is an admittedly unoriginal one that has recycled many ideas from other movies, but its screwball comedy sensibilities fetchingly pay off more often than not. The proceedings are aided immeasurably by a game cast of bright faces, with Jason Lee (2002's "Stealing Harvard"), Julia Stiles (2001's "O"), and Selma Blair (2002's "The Sweetest Thing") charismatically leading the way.

"A Guy Thing," which acquires its name from one of the more unlikely good running jokes in the piece, opens at the bachelor party of nice guy Paul Morse (Jason Lee), who is to marry the organized and well-to-do Karen (Selma Blair) in less than a week. After having a few too many drinks, Paul wakes up the next morning in bed beside Becky (Julia Stiles), one of the Tiki girls hired to entertain the night before. Paul has no recollection of what happened, while Becky assures him that they merely slept next to each other. As the countdown to the wedding continues, Paul finds himself spiraling down a road of lies, not helped by the revelation that Becky is Karen's cousin and Maid of Honor. And worst of all, Paul starts to find the freespirited nature Becky holds as a more attractive option than his pre-planned life of normalcy with Karen.

A lightweight, but undeniable, entertainment, "A Guy Thing" works more successfully as a comedy than a romance, if only because more time is attributed to the former. A few scenes are gems in the way they are performed and edited for maximum comic effect, including an episode in which Paul fakes bowel troubles in order to avoid coming in contact with Becky, and another dealing with Paul's horrific discovery that he has contacted crabs while in a business meeting with his soon-to-be father-in-law (James Brolin). Meanwhile, the potential romance that blossoms between Paul and Becky works because they are both wonderfully likable and intelligent individuals, but not enough time is spent developing the relationship for the predictable climax to have the desired satisfying payoff.

The actors are easily the picture's highlight, most of which would be fun to watch even if they were simply reading the phone book. Following up his lead role in the throwaway "Stealing Harvard," Jason Lee has better writing and flashier chances to show off his comedic abilities here, even if the part of Paul isn't significantly different. Julia Stiles, never known to give a weak performance, is luminous as the slightly wild and always charming Becky. While Stiles isn't onscreen nearly as much as you might expect, when she is she steals the show and makes it instantly easy to see why Paul would be smitten with her. In the somewhat thankless part of fiancee Karen, Selma Blair is blessed by the kind of smart writing that avoids turning her into a bitchy caricature and, instead, chooses to present her as a sympathetic presence. In supporting roles, Shawn Hatosy (2002's "John Q"), as Paul's best friend Jim, and the always-reliable but lately underused Julie Hagerty (2001's "Freddy Got Fingered"), as Paul's mom, are most memorable.

Had Paul and Becky's relationship been given a few extra scenes, his eventual choice in being with the person that will make him happiest (Becky) over the person who is safer (Karen) would have had a more stimulating effect. Still, "A Guy Thing" is a charmer when it wants to be, if only because the characters on display are ones we enjoy spending time with. They are infinitely more mature, and their escapades genuinely funnier and heartfelt, than anything that is offered in "Just Married."