Sibling Ribaldry

THE FARRELLY BROTHERS HAVE something they want to show you--and it isn't their new movie. In fact, it's something you'd probably rather not see at all. Something of Peter's. Something anatomical in nature. The Farrellys have concocted a variety of clever ploys designed to get you to look at it. Bobby, 40, is the straight man, all innocence as he lays the trap. Then Peter--lankier, edgier and a year older--delivers the coup de grace. You may think you're going to be examining a mysterious blotch on Peter's torso, or checking out his new watchband. The reality is a good deal more shocking, but as actress Cameron Diaz puts it, ""When a director shows you his penis the first time you meet him, you've got to recognize the creative genius.''

Or contact a lawyer. The truth is that in person, the Farrelly brothers' cheerfully retrograde humor eventually wins you over. And it pales in comparison with what this pair of writer-directors will whip out once they get you into a multiplex. The Farrellys' riotous new love story, ""There's Something About Mary,'' has been slaying preview audiences. ""What "Animal House' was for the '70s, this movie is for the '90s,'' says Fox production president Tom Rothman, whose studio recently signed the brothers to a three-year deal. For the Farrellys, the film may represent a breakthrough of sorts. Their 1994 lowbrow smash ""Dumb and Dumber'' grossed $340 million worldwide. But the credit went to Jim Carrey, not ""the idiots running the show,'' as Peter puts it. Critics liked their follow-up, ""Kingpin,'' though it drew about as many people as you'd expect for a comedy about a bowler with a rubber hand and his Amish sidekick. ""Mary'' could be the sleeper hit this summer desperately needs--and bring the Farrellys the visibility that ""Dumber'' didn't. ""For us, this is the perfect movie,'' says Peter. ""We co-wrote it, we directed it and we got everything we wanted into this movie--things that we never thought we'd be able to get away with.''

You won't believe they got away with some of it, either. There are jokes at the expense of the handicapped. There are glimpses of anatomy and bodily emissions you'd never expect to see this side of an NC-17 rating. Bad things happen to small dogs. But it's all carried off with a good-natured finesse that leaves you more likely to crack up than cringe. As the film opens, we meet our antihero, high-school loser Ted Stroehmann (Ben Stiller). The only thing worse than Ted's haircut is his luck with the ladies--until the day he rescues a retarded boy from the wrath of a bully. The boy's beautiful sister, Mary (Cameron Diaz), rewards Ted's sensitivity by asking him to the prom. But before young Ted can consummate his dream date, he suffers a disastrous run-in with the zipper on his rented tux. A dozen years later, Ted is still obsessed over what might have been, so he hires a sleazy private eye (Matt Dillon) to track down his lost love. The private eye also falls in love with Mary, setting off a hilarious showdown for her affections. The film boasts a handful of scenes that will likely join the pantheon of high-school legend, but if it has a problem, it's that the brothers seem content to bunt for long stretches between home runs. And, let's face it, you've likely seen more sophisticated camera angles in your local 7-Eleven.

Not that the brothers care, necessarily. ""The camera for us is not a big thing,'' says Peter, drawing a distinction between the Farrellys and that other, more upmarket, team of writing-directing brothers. ""I really respect the Coens, but we're the anti-Coens. Nobody analyzes our movies--and we don't want them to.'' The brothers' casual approach to their art befits their status as Hollywood walk-ons. The brothers spent their youth ""catching frogs, playing baseball and chasing girls,'' in Cumberland, R.I., and credit their sense of humor to ""a lot of funny bastards'' in the neighborhood and to their father, a doctor prone to playing pranks involving dead family pets. ""He's a sick man,'' says Peter.

The Farrellys would eventually turn sick pranks into a career. Peter took to writing first. After bouncing around a bit in a typical early-20s funk, he enrolled in grad school at Columbia. His first novel, ""Outside Providence,'' was published in 1988, followed by this year's semiautobiographical ""The Comedy Writer.'' But early on, Peter realized that ""this book stuff could take forever.'' He turned to screenplays, moved to L.A. and eventually dragged Bobby along. For years, the pair supported themselves comfortably, writing movies that never got made. Until ""Dumb and Dumber,'' that is. The brothers were signed on to produce and direct their own script back when it was to be no more than a micro-budgeted lark. A then unknown Jim Carrey was hooked by the premise--two numskulls' road trip to Aspen--and signed on after ""Ace Ventura'' made him a star. Despite a complete lack of prior experience, Peter says he found himself eminently capable of directing the film. ""I'm telling you, this is the biggest scam in the world,'' he says. ""I wish everybody could direct one movie because you know what? Everybody could.'' Indeed, the brothers profess to shun movie-industry affectation of any kind. ""As soon as you're real cool or slick, you're not funny anymore,'' says Bobby. ""We'd rather be a couple of idiots who are funny.''

Everybody agrees that these idiots know what they're doing. The laid-back party atmosphere on the set lulled Stiller, for one, into shooting scenes that would otherwise have been humiliating, to say the least. ""To me, their genius is that they get actors to do things you never thought you'd do,'' Stiller says. ""Not until months later, when you see it up on a screen, do you realize what you've done.'' And as you might expect, Fox executive Rothman waxes rapturously about the Farrellys' talent for ""deceptively smart comedy,'' and compares them to the Marx Brothers. Yeah, OK--but has he ever been taken in by one of Peter and Bobby's trademark gags? Has he seen . . . it? ""I have been flashed,'' he admits. ""It wasn't a pretty sight. In fact, I'm still recovering.''