Peter and Bobby Farrelly gross out audiences

What’s the most unforgettable image of ’98? Could it be John Glenn saluting from the shuttle? Mark McGwire swatting his 62nd homer? Dr. Kevorkian doing his thing on 60 Minutes? Nah. The most indelible visual had to be Ben Stiller’s nether parts stuck in a zipper. Try as we might, we just can’t erase that repulsive, wince-inducing close-up from There’s Something About Mary. Of course, why would we want to? The shot was downright hilarious. And for that, we can thank the brothers Farrelly.

With Mary, cowriters and directors Peter and Bobby became the undisputed Visionaries of Vulgarity, the Kings of Crass. Admittedly, it’s a prize they’ve had their eyes on for years. First came their 1994 megahit Dumb &amp Dumber (lots of snot and poop humor), then their less successful — though thankfully no less revolting — follow-up, 1996’s Kingpin (in which the Farrellys graduated to vomit and bull semen). But with this summer’s R-rated charmer, the siblings hit new highs — and lows. The genius of Mary? It manages to be a heart-tugging romance — snaring a whole new class of Farrelly fan (namely, female) — while upping the stomach-churning gags: Need we mention the old lady swapping spit with her Border terrier? Or Cameron Diaz applying a certain protein-rich hair gel? Prim and proper folks may have smelled the apocalypse, but the rest of us ate it up. Mary‘s domestic gross: $173 million.

”It’s been a gas,” says Bobby, summing up the year with an appropriately flatulent metaphor. ”People are trained to think we’d never go as far as we do. So the surprise is funny. If everyone starts doing it, which I’m sure they will, it might not be as funny.”

In fact, everyone has already started doing it. Even before Diaz’s seminal ‘do, South Park and Adam Sandler were busy offending America’s sensibilities. But it was Mary‘s unexpected killing at the summer box office that sent the signal to the world: Wordy smart aleck Jerry Seinfeld has left the zeitgeist. Welcome to the Age of Adolescent Entertainment!

No doubt the nation’s appetite for all things tasteless will eventually subside. But for now, Peter and Bobby (41 and 40, respectively) are flush with success. This after they spent a decade selling unproduced screenplays (15, to be exact), and Bobby struck out as an inventor (his circular beach towel — so you don’t have to shift it when the sun moves — didn’t exactly fly off the shelves). Next up for the sibling auteurs: Stuck on You, a Siamese-twin comedy featuring Woody Allen and a yet-to-be-named costar. ”In no way are we making fun of Siamese twins,” promises the ever-sensitive Bobby. ”We love these characters.”

Sounds intriguingly ludicrous. Still, it’ll be hard to top Ben Stiller’s bloody crotch. Which, we should point out, wasn’t actually Stiller’s. For the infamous close-up, the Farrellys ordered a four-foot-tall zipper and a kickball-size gonad. Sadly, the zipper broke, and the brothers had to take the scary-looking contraption to a local tailor to be fixed. The poor fellow practically had a heart attack. ”That’s the mark of good comedy,” Bobby says, ”when you got people almost dying.” Consider us slain.