As best as I understand them, here are the core comic principles guiding the new movie 'For a Good Time, Call...':

Phone sex is funny.
Watching men masturbate during phone sex is funnier.
Watching celebrity men masturbate during phone sex is the funniest thing since a clown slicing bread.

There's a decent joke in 'For a Good Time, Call...' but just one, and it's played over and over again (see: principle #1).

The film is about two young women forced by circumstance to become roommates and start a phone sex line. Lauren (Lauren Anne Miller, who also co-wrote the film) gets dumped by her longtime boyfriend just as Katie (Ari Graynor) loses the rent control on her gorgeous Manhattan apartment. A mutual friend, Jesse (Justin Long), introduces them and suggests they bunk up -- but he'd already tried to hook the pair up once in college and it didn't go well, which means Lauren and Katie will live together but they won't like each other, until they do like each other, until they stop liking each other, until they realize they're being stupid and start liking each other again.

That is rarely the arc that genuine human relationships take, but this is a movie and there are rules governing these sorts of things. 'For a Good Time, Call...' is a romantic comedy about the love between two female friends, a XX chromosomes version (with a XXX hook) of the bromances regularly churned out by comic movie mogul Judd Apatow and his stable of filmmakers and stars (one, Seth Rogen, is Miller's husband). It's a clever idea, and Miller, Graynor, and Long have a appealing onscreen rapport. But if the structure feels like something out of the world of Apatow, the material doesn't quite reach his exacting standards.

As the two women move in together, Katie is moonlighting as a phone sex operator, accepting calls from a stringer in exchange for a commission; the ever-enterprising Lauren sees an economic opportunity and suggests they go into business for themselves. The phone sex line is both the movie's biggest hook and its primary stumbling block. It's treated exactly as you would expect: as an excuse for cheap sexual humor, much of it performed by some very recognizable actors and directors making cameos as Lauren and Katie's clients.

Don't get me wrong: I enjoy cheap sexual humor as much as the next guy. But in order for cheap sexual humor to work it's got to be clever as well as vulgar, and beyond a few inventive terms for various portions of the human anatomy, 'For a Good Time, Call...' doesn't bring anything new to the table. And in this day and age of Internet porn, cybersex, Skype-sex, sexting -- not that I have used any of these things or am even all that familiar with what they are but I think a friend of mine told me about them once -- who uses a phone sex line anyway?

For its moments of lightness and charm, 'For a Good Time, Call...' feels about as relevant as its 976 number gimmick. Director Jamie Travis keeps the energy level high but his juggling of the movie's various subplots, particularly in the final act, feels clumsy (one involving Lauren's uptight parents vanishes without a resolution). The finished product is more likable in theory than execution. It's not a terrible time. It's just not a particularly good one.

'For a Good Time, Call...' opens in select theaters on August 31.

Matt Singer is a Webby award winning writer and podcaster. He currently runs the Criticwire blog on Indiewire and co-hosts the Filmspotting: Streaming Video Unit podcast. His criticism has appeared in the pages of The Village Voice and Time Out New York and on ‘Ebert Presents at the Movies.’ He lives in Brooklyn with his wife, dog, and a prop sword from the movie ‘Gymkata.’