There aren't many principles Hollywood holds sacred, but there are a few.

Among them: Summer is a time to fill with mega-budget movies. Movies need to do huge business on their opening weekends or they sink like stones. And blockbusters are preceded by that elusive sense of anticipation universally referred to as "buzz."

This summer, those principles were roundly trounced.

Why? Maybe it was just the excruciating heat that drove people into cool, dark theaters.

Here in Hollywood, frankly, my dear, nobody gives a damn because the summer box office will add up to about $3 billion, a few hundred million dollars ahead of last year's $2.6 billion. More than that: The number of tickets sold is up 8.5 percent.

"That means that attendance is up; it's not just that ticket prices are higher or whatever. It means you're up across the board," says Paul Dergarabedian, whose company, Exhibitor Relations Co. Inc., maintains box office statistics.

"Even those of us who thought it would be a big summer never thought it could be this big," says Tom Sherak, who chairs the motion picture group for 20th Century Fox. His studio had a little movie this summer called "Star Wars: Episode I: The Phantom Menace." It has taken in $420 million in the United States and about $300 million abroad. That makes it the second most successful movie in history, after "Titanic." He adds: "But I believe movies are contagious. When you see movies you like, you go back to the movies."

And so it was. The summer of '98 was the summer of $100 million budgets. This summer--oh, glory be--was the summer of $100 million revenues. The big winners came shooting out of the can week after week: "Notting Hill," "Austin Powers: The Spy Who Shagged Me," "The General's Daughter," "Tarzan," "Big Daddy" and on and on. Then in the second half of the summer, "Inspector Gadget," surprise hit "The Blair Witch Project" and "The Sixth Sense." This summer, 11 films have cracked the $100 million box office barrier in the United States alone. And "American Pie" will soon cross that threshold.

Observers noted that many of the successful summer films were driven by character and story, not special effects. What a concept. "It wasn't really the summer of the event-type of movie," Dergarabedian says. "It was more 'Austin Powers,' 'The Haunting'--none of those are Stallone or Schwarzenegger action pictures."

"American Pie," a coming-of-age comedy about four high school seniors that has grossed $97 million, cost only $11 million to make. Adam Sandler's "Big Daddy," about a schlemiel grown-up adopting a tot, cost $34 million and has taken in $160 million so far.

The conventional blockbuster movie wisdom got turned on its head. After last year's slate, which was crowded with expensive films like "Godzilla," "Lost in Space," "Armageddon" and "Lethal Weapon 4," this summer was filled with movies that cost far less. Studios scaled back radically and made a strategic decision to stay out of the way of "The Phantom Menace," the summer's only can't-miss film.

It was a strategy that worked. After turning out in droves, despite tepid reviews, to see Anakin Skywalker and Jar Jar Binks, audiences came back to see Julia Roberts twice--in "Notting Hill" and "Runaway Bride"--or to see raunchy comedies like "Austin Powers" or to be scared witless by horror films from "The Haunting" to "The Sixth Sense."

"The movies that worked were good, fun, communal experiences," says Brian Mulligan, co-president of Universal Studios, who made the risky choice to put "The Mummy" and "Notting Hill" on either side of "Phantom Menace."

The only other mega-budget film of the summer, "Wild Wild West," was dogged by reports that scenes had to be reshot and by poor word-of-mouth after audiences saw it. The movie's budget reportedly ballooned as high as $180 million; so far it has taken in only $112 million.

One movie that had no buzz going for it--"The Sixth Sense"--has turned into one of the summer's biggest hits, taking in more than $20 million over each of the past four weekends, a total of $139 million so far.

The Disney horror film, starring Bruce Willis and a creepily convincing little kid, was slated to open in the fall, but got moved up to late August and then mid-August, before the studio could really establish a marketing campaign.

But that didn't matter.

Disney distribution president Chuck Viane says "Sixth" took off the old-fashioned way: Word got around that it was a great movie. "This is the true definition of a sleeper," he says. "It's a movie the public made into a hit. The public sampled the movie, and came out and told their friends, 'You have to see this film.' And people are going back on their own; they want to see what they missed."

And then there was "The Blair Witch Project," which broke absolutely all the rules. It sneaked up on theaters over Internet chat sites and took establishment Hollywood by surprise. The film started out with virtually no marketing budget but became the most profitable film of all time, costing $350,000 to make (after technical improvements by the studio; the initial cost was $35,000) and taking in $128 million so far.

"You do not have to have a film that cost $100 million and pay actors $20 million in order to create a viable product in the marketplace," says Amir Malin, president of Artisan Entertainment, the art-house studio that distributed the film. "Something that's unique and original, whatever genre it appears in, will succeed in the marketplace."

"Blair Witch" also broke with the accepted practice of opening a movie on thousands of screens and watching it quickly lose ground. Instead, the film started at 27 art-house theaters before its massive success shot it onto 1,100 screens across the country.

Strangely enough, there were relatively few films for younger children during a season when kids are most able to go to the movies. "Tarzan" was a big hit, but otherwise there was little competition for the children's movie-going dollar. "Inspector Gadget" was not heavily hyped, and "Iron Giant," widely praised by critics but barely promoted by Warner Bros., hardly registered with audiences. The gentle "A Dog of Flanders" flopped last weekend, opening with only $900,000. Similarly, "Dudley Do-Right" tanked, taking in only $800,000.

The lesson may be that family movies are on the outs, as even little kids look to get in on the culture's hippest trends, which this summer was nasty humor a la "South Park: Bigger, Longer & Uncut" and raunchy, adolescent comedy like "American Pie."

One disgusted mother, Maureen Foster, wrote in a column in the Los Angeles Times last week: "By mid-July we'd run out of things to see as a family. My kids counted up the movies in the paper, and out of 35 films, 20 were R-rated, six were PG-13, five were PG and four were G. This is Hollywood's idea of summer fare?"

But Universal co-president Stacey Snider says it's harder than ever to create a movie that will appeal to entire families. "It's about finding something that's edgy enough to be cool, but not too intense to frighten kids," she says. "That's threading the needle very carefully."

Says Fox's Sherak: "You say 'family movie,' and studios get cold shivers up their back. Kids have become more sophisticated. They don't want to see movies they think might be made for their younger brothers."

And what of the summer's most anticipated artistic film, director Stanley Kubrick's "Eyes Wide Shut"? Though it had more buzz than any summer movie except "Star Wars," and it had Tom Cruise, whose movies routinely do $100 million, it has not been a hit with the public. So far, "Eyes" has barely covered its production cost of $65 million.

Like any good business folks, Hollywood executives are busy learning the lessons of their fruitful summer of 1999. "Look, the audience is getting younger," says Sherak. "By 2003, there will be more teens in this country than ever before. The studios will make movies for them. Those movies will cost less, and it will be content that drives those movies, not stars."

Says Malin: "For many films, you do not need to spend a small fortune. You just have to work it hard."

SUMMER'S BIGGEST DIPPERS

Total domestic grosses for the top dozen films of the summer season:

1. "Star Wars: Episode I: The Phantom Menace": $420 million

2. "Austin Powers: The Spy Who Shagged Me": $204 million

3. "Tarzan": $166 million

4. "Big Daddy": $160 million

5. "The Mummy": $155 million

6. "The Sixth Sense": $139 million

7. "The Blair Witch Project": $128 million

8. "Runaway Bride": $124 million

9. "Notting Hill": $115 million

10. "Wild Wild West": $112 million

11. "The General's Daughter": $101 million

12. "American Pie": $97 million

Source: Exhibitor Relations Co.

MOVIE TRIVIA, SUMMER 1999

* Only actor to headline in two films: Julia Roberts, in "Notting Hill" and "Runaway Bride." (And the only actress in history to have six films earn more than $100 million.)

* Only director with two films in release: John McTiernan ("The Thomas Crown Affair" and "The 13th Warrior").

* Cost of "Wild Wild West": $180 million (estimated).

* Cost of "The Blair Witch Project": $350,000.

* Most convoluted Hollywood record: first time three films grossed more than $20 million in a single weekend: "Tarzan," "Austin Powers" and "The General's Daughter" (all released on June 18).

* Big winner: "The Blair Witch Project," now considered the most profitable movie in history.

* Big winner, collegiate division: The University of Central Florida film program, attended by the makers of "Blair Witch," which reported that 250 students signed up for its "Introduction to Film" class this fall, compared with 48 last year.

CAPTION: This summer, less was more and more was less: "Blair Witch Project," left, and "Wild Wild West."