Actually, I can’t tell. I haven’t seen “The Guardian.” I’ve only seen the trailer, which is why I already know everything that happens in the movie except how it ends.

Audiences are always complaining that trailers give away too much, and in that respect, “The Guardian” might be the guiltiest offender since the famously blabby trailer for " What Lies Beneath ," which made it clear to anyone with brain activity that Harrison Ford totally did it. But it’s an even bigger sin these days because, thanks to the Web, movie trailers have become as natural a form of disposable entertainment as the movies themselves. In some workplaces, watching trailers at Apple.com is the new must-see TV. “People watch them for fun now,” says Valerie Van Galder, Sony’s vice president of marketing, “and that’s made them a huge priority for us.” Studios carefully monitor downloads of their trailers, and they interpret the data like it’s a less-reliable form of audience tracking polls (which, admittedly, are pretty unreliable in their own right). As a result, the cost of a dud trailer has never been higher, whereas a memorable one can almost single-handedly launch a movie.

Despite their growing importance, however, most Hollywood trailers are as bland and conventional as the movies they advertise. Which doesn’t necessarily make them “bad.” The folks who cut the “Guardian” trailer aren’t stupid. The film is basically “Top Gun” with boats and waves, and its primary audience is people who want an easy, sure thing for their $10 movie ticket—in other words, people who want to see a movie they’ve already seen before. If you had to boil down the strategy of the “Guardian” trailer to one sentence, here it is: “This movie is exactly what you think it is.” It’s not bold, but at the risk of sounding cynical, it’ll probably work.

Not everyone’s playing it safe, though. A new pair of fall-movie trailers set fire to the rule book, and the result, in both cases, is a spot that’s thrilling on its own terms and flawless in its function: to put as many butts in the theater as possible.

‘Little Children’ (New Line)

The film, written and directed by Todd Field (“In the Bedroom”) and based on the novel by Tom Perrotta, is a dark, quirky tale of suburban ennui and infidelity starring Oscar darlings Kate Winslet and Jennifer Connelly, plus rising star Patrick Wilson (“Angels in America”). The trailer could have easily, and effectively, played up the film’s mordant humor and drafted off of its obvious forebears—“American Beauty,” “Election” (which was based on another Perrotta novel), even “Desperate Housewives.” Instead, Mark Woollen and Associates, the company New Line hired to cut the trailer, came up with something completely different.

The most notable thing about the “Little Children” trailer is the remarkable sound: there’s virtually no dialogue from the film and no music, only the rumble of a distant train drawing closer and closer, then blowing by at the climax of the spot. We see visual hints of a quiet suburban life infected by an affair, but that’s all we get. “It has an ominous quality to it, and it conveys this sense of stories crashing together at the end,” says the film’s coproducer, Samuel Berger, who adds that he and his business partner Ron Yerxa deserve little credit for the trailer beyond having the good sense to approve it. The trailer was actually Woollen’s first try. The production team experimented with more conventional approaches, even at one point scoring it with Simon & Garfunkel’s “The Sound of Silence,” “and I have to say, it was tempting,” Berger admits. “A trailer with music made it feel more universal, and there’s something to be said for that. We are trying to reach an audience, after all. But we ended up going with our original instinct. We do feel out on a ledge a bit, but that’s exciting. And we were just stunned by that trailer.”

Since its Web premiere on Aug. 31, the spot has been a buzz machine on movie news and gossip sites, drawing praise for its bold approach and helping to raise the profile of an ambitious, but small, art-house film. “I’m getting a lot of phone calls about it,” says Mary Carrillo, head of creative advertising for New Line Films. “I’ve been doing this for 10 or 15 years, and there’s been about three or four trailers in that time that have really resonated. This is definitely one of them.”

‘The Grudge 2’ (Sony)

On the opposite end of the cinema spectrum from “Little Children” is this flashy, Japanese-horror remake starring Sarah Michelle Gellar. Personally, I passed on the first installment; it seemed to me a poor man’s “The Ring,” with Gellar being a destitute man’s Naomi Watts. I was even less interested in the sequel—until I caught the trailer during a trip to the movie theater last month and it scared the bejesus out of me. I was so surprised by it that I briefly considered going back and checking out the first “Grudge” just in case it was this good.

Like the “Little Children” spot, this trailer works because of its unconventional use of sound and pace. Unlike most horror-movie trailers, the “Grudge 2” spot is quite slow and largely silent. It’s the standard length for a trailer—maybe even a few seconds shorter, says Van Galder, who supervised it—but it feels much longer. It oozes and slithers into your head. New Line’s Carrillo, who admires it, says it’s “like a rubber band being pulled back. I like that they didn’t just throw a bunch of slasher images on the screen.” The scary images are definitely there, but they seem to arrive a half second after you expect them, pulling up the hairs on your neck—and then they’re gone. The rhythms throughout the trailer are completely out of whack, which is exactly how good horror movies work: they keep you off-balance and uncertain.

Most horror and action-movie trailers, says Van Galder, begin by teasing some plot and some characters and then climax with what she calls “the montage of mayhem”: a rapid-fire series of splintered images—an explosion, someone running or screaming or falling, a car crash, etc.—that attempts to overpower the senses with spectacle rather than mood. It’s usually a sign that the movie, in a word, stinks. The “Grudge 2” trailer, cut by a production company called Trailer Park, goes in the opposite direction. “[Trailer Park has] a wonderful sense of pacing and terror and how to turn two and a half minutes into something really terrifying,” Van Galder says. “The best horror trailers use silence as effectively as sound, and the pacing is very strategic. It’s not frantic. It feels creepy.” Sony’s reward: 1.5 million downloads of the trailer from various Web sites, according to the studio. Which should help get the “Grudge 2” off to a nice start at the box office, whether the movie itself measures up or not.

Movie Previews

Click below to watch the trailers:

‘The Guardian’

‘Little Children’ ‘The Grudge 2’ false