When Matt hears from the "Bagel Guy" (MICHAEL C. MARONNA) that Nicole is now engaged, it just about breaks him. Yet, he decides to do something about that and his other problem, and that's give up sex or any other sort of sexual behavior for Lent. Most everyone thinks he's crazy and/or won't be able to accomplish the task, with his co-workers secretly setting up a website and betting pool related to such matters and when he'll fail.

Matt thinks he'll have no problem completing his task, but then meets Erica (SHANNYN SOSSAMON), a young and attractive woman who scours porn sites for a living working for a company that provides software to filter them out. Although Matt tries to keep things platonic, he and Erica begin developing feelings toward each other, although he decides not to tell her of his quest, a point that leaves her and her roommate, Sam (MAGGIE GYLLENHAAL), wondering what his story might be.

As the days wear on and Matt's older boss, Jerry (GRIFFIN DUNNE), decides to try his hand at abstinence as well, various people try to make Matt succumb to the temptations of having sex so that they can will the ever-growing betting pool. Yet, he tries to hold on and hopes that Erica can wait for his unique goal to be over.

Of course, all ads are supposed to give you a taste of what they're selling and entice you to buy or attend their product. In that sense, the ad works as it implies a playful, but obviously adult romantic comedy about a young man opting to forgo sex for the period the title suggests. We're supposed to wonder why and whether he'll succeed.

Yet, the whole bit about "no sex" - obviously intended to refer to that abstinence - couldn't be further from the truth. While the character might not engage in sex - an activity whose true definition is now debatable - during the 40-day quest, he does before and after the undertaking, while a cornucopia of sexually related material and activity is present even during that. In fact, if one were looking for the definition of a film with just one thing on its mind, this would be it.

A mixture of a classic romantic comedy with a teen sex comedy romp, the film takes what's essentially just a one-note premise and milks it for everything it's worth in an attempt to generate laughs and enough material to fill the ninety or so minute runtime.

Accordingly, the film - written by novice screenwriter Robert Perez - plays out like an elongated, big budget version of a sitcom. One can imagine an episode of "Three's Company" where Jack decides to try the abstinence route only to have his friend Larry think he's crazy while his roommates Janet and Chrissy (or Terri and Cindy) and many other curvaceous beauties purposefully or accidentally drive him crazy just by doing anything and everything that would arouse a typical heterosexual, male teenager.

Thankfully, the picture is a bit more complicated than that '70s era sitcom, although not by much and its heart, mind and another body organ are pretty much in the same place. As directed by Michael Lehmann ("The Truth About Cats and Dogs," "Heathers"), the film plays out in a fashion that will surprise few, but fortunately avoids most of the gross out humor used in other teen/young adults romps such as the "American Pie" films.

Hedging his bets, Lehmann strives to keep both sides of his target audience - namely young couples - happy by balancing all of the sex and scantily clad or nude women (for the guys) with the traditional elements and formula of the romantic comedy genre (for the ladies).

The result is mildly entertaining, but that's more due to the cast and their performances than any of the romantic/sex comedy predicaments, complications and humor that the filmmakers manage to conjure up and mix into the proceedings.

Unless one is an over or under-stimulated young male, few of the film's attempts at comedy will come off as laugh out loud funny, or even make much sense (including the all-important basic premise of giving up sex for 40 days). That's not only because most of the sexual shenanigans are predictable and ultimately redundant, but also because too much of the material comes off as unbelievable, juvenile and/or contrived.

Beyond pivotal misunderstandings (important for romantic comedies) that could be remedied by having the upset parties simply converse, there are numerous scenes that are moronic and/or just wouldn't happen, such as parents talking about their sexual practices and history in front of their adult kids (one of whom is a priest in training).

The same holds true for a scene in which the protagonist brings his would-be girlfriend (who's dressed only in some flowers and skimpy panties) to orgasm without touching her. While that's possible, it's certainly not probable for the protagonist, the story and everything that preceded that moment since up until that point he's tried to avoid even the most minor form of stimulation (something a mostly nude and orgasmic young woman would provide ample amounts of).

Of course, it doesn't take rocket scientist or Hugh Hefner to realize that none of that's meant to be taken seriously, and instead is present to generate laughs and/or titillate the viewer. Far more successful at the latter than the former (especially if you're a young male), a bit more of a sophisticated effort at generating laughs certainly would have behooved the production and thus one's enjoyment of it.

What the film does have going for it is Josh Hartnett ("Black Hawk Down," "Pearl Harbor") as the comically troubled and sexually frustrated protagonist. Although there's nothing to his performance that could be confused with comic genius, it's generally a winning effort. There's no denying that the young and still upcoming actor is charming and delivers an amusing take on his character. It's just too bad both aren't in a better picture.

The same holds true for Shannyn Sossamon ("A Knight's Tale") as his female counterpart who works well playing off and with his character. The chemistry between them works and she certainly has the looks, temperament and charisma for the genre, and feels natural in the role, even if the standard and predictable, relational ups and downs - and thus her motivation at times - feel far too contrived and unrealistic.

Supporting performances don't fare as well, with most of the women who are present being objects of desire for Matt and others. Then there's the ex-girlfriend - played by Vinessa Shaw ("Corky Romano," "Coyote Summer") - who's the standard, one-dimensional such character whose meanness undermines the whole aspect of the protagonist being hung up on her for much of the film (we never see or sense what he saw in her other than outward appearance).

The men's function is to bet, laugh at or attempt to undermine his goal to win the bet, with Paulo Costanzo ("Josie and the Pussycats," "Road Trip") getting most of the screen time as the obnoxious roommate. Since little of that is overly clever or complex, the resultant performances and characters consequently suffer. Griffin Dunne ("After Hours," "Who's That Girl?") also shows up as the protagonist's boss who similarly tries abstinence, but is then reduced to having to play some embarrassing/humiliating material.

If not for the presence and chemistry between the leads, the film would have been yet another awful or at least run of the mill sex comedy. As it stands, however, it's still not very good, as it's lacking enough smarts, sophistication and/or novelty to stand out from the crowd. Although it thankfully doesn't feel as long as its title, the film wears out its welcome and ability to milk its premise long before its runtime is done. "40 Days and 40 Nights" rates as a 4 out of 10.