It takes a while for Hollywood to guess right and give birth to a hit franchise. But this summer heralds the return of a whole new class of mature, reliable brand names — the new generation of surefire household hits.

Remember the glory days of James Bond? Try “The Bourne Ultimatum.” What about all those Disney musicals that were the reliable family staples of summers past? Now we have “Shrek,” “Harry Potter,” and a new kid on the block, “Nancy Drew” (which has already been extended, before the film’s release, for a sequel).

The weekend of July 4 will be dominated by a franchise that many thought was a joke — until they eyed an Internet teaser and saw that one of action filmmaking’s biggest names, Michael Bay, was taking charge of it all: “Transformers.”

Like clockwork, from this week’s “Pirates of the Caribbean” premiere to “Rush Hour 3” in August, the summer franchise feast is in full force. Here’s a breakdown of the season’s top films, from bigbudget franchises to the occasional hopeful outlier:

THE UNDERDOG TRIO:

The Summer’s 3 Biggest Surprises

“Rocket Science” (August 10)

The last few years have had seen runaway hits of a quirkier variety, with unconventional heroes at their center: In 2004, it was “Napoleon Dynamite,” in 2005 it was “The 40-Year-Old Virgin,” and last year it was the Sundance/Oscar heavyweight “Little Miss Sunshine.” Like the nerds and virgins who carried those films, this year’s antihero is waiting to be discovered in mid-August: a stuttering debate team hopeful, traumatized by his parent’s divorce and in love with a girl who thinks she’s better than he is.

Directed by Jeffrey Blitz, who won the best directing award at Sundance for the film and helped repopularize documentary films with his 2002 spelling bee documentary “Spellbound,” “Rocket Science” is a purely fictional film, set in the competitive world of amateur debating. But it is in the award-worthy performance of 19-year-old Reece Thompson that sets the movie apart. Ignored by a mother who keeps cycling through boyfriends, beat up by a criminally minded brother who spends his days stealing, and struggling to find his voice through a stutter that makes it nearly impossible to win a debate — not to mention the girl who recruited him to the team — Mr. Thompson is the personification of teenage longing and loneliness.

Lurking behind the films with $100 million budgets, this is the true gem of the summer — the diamond in the rough.

“Sicko” (June 29)

The other driving force behind the documentary boom of 2002 was Michael Moore, who has receded recently from the spotlight but promises to crash back to the fore with “Sicko,” his take on the state of the American health care system. The film made its world premiere overseas at the Cannes Film Festival (which runs through Sunday), just as Mr. Moore is being investigated by the Bush administration for orchestrating a stunt in which he took ailing September 11 responders to Cuba for treatment. If the hordes who saw “Bowling for Columbine” and “Fahrenheit 9/11” show up this time around, “Sicko” may be the talker of the season. (The hitless Weinstein Company is no doubt banking on it.)

“Knocked Up” (June 1)

What does it say about a modern comedy that it can make grown men cry and women belly laugh, that it can balance jokes about abortion with the sight of five immature stoners jumping up and down over a newborn? Director Judd Apatow and company — the same crew that somehow simultaneously celebrated and poked fun at celibacy in “The 40-Year-Old Virgin” — return with what might be the year’s most emotionally charged comedy.

THE REST OF THE PACK

“Pirates of the Caribbean: At World’s End” (May 25)

“Spider-Man 3” and “Shrek the Third” have already taken big bites out of the summer box office, but “Pirates” hopes to eclipse those hauls, hitting theaters only a year after the second chapter broke box office records. The story starts with the daring rescue of the swaggering Jack Sparrow (Johnny Depp), but the real question is how much is too much: Will audiences appreciate three hours of “Pirates” adventures on the high seas?

“Mr. Brooks” (June 1)

So is he or isn’t he? Is Kevin Costner still a movie star, or another has-been from a bygone era? For that matter, he isn’t the only questionable big-name star here — he’s flanked by Demi Moore, who has been missing from movie screens for quite a while. The film tells the story of a serial killer, played by Mr. Costner, who reverts to an alter-ego when he acts on his urges. It’s a modern, literal twist to the traditional Jekyll-and-Hyde formula, with Ms. Moore in pursuit as a detective.

“Ocean’s Thirteen” (June 8)

If 2001’s “Ocean’s Eleven” had too many characters to keep straight, and 2004’s “Ocean’s Twelve” was just this side — or maybe that side — of being too cute for its own good, then what will happen this time around, with 13 criminals and a hard-boiled casino heist? In this chapter, George Clooney, Brad Pitt, and the crew are joined by Al Pacino, the owner of yet another casino the good ol’ boys aim to loot.

“Fantastic Four: Rise of the Silver Surfer” (June 15)

Here’s the title that has had comic fanboys quaking in anticipation: Not only is Silver Surfer finally coming to the silver screen, but legions of readers know that this most certainly means his nemesis, Mephisto, is not far behind. While the first “Fantastic Four” did big business — grossing more than $150 million — it was savaged by fans of the comic franchise, and it’s clear that in turning to the comic’s biggest hero and villain — even going so far as to promise a scene in which the surfer is separated from his board — 20th Century Fox hopes to build this into the next “Spider-Man”-caliber summer brand.

“Evan Almighty” (June 22)

Not just a sequel to the popular Jim Carrey-as-God “Bruce Almighty” from 2003, “Evan Almighty” gives all those “Office” and “40-Year-Old Virgin” fans another heaping dose of Steve Carell’s dry and delightful droll. In this supernatural — and massively over-budget — twist to the Carrey story, Mr. Carell plays a congressman who is charged by God with building an ark for the coming flood.

“A Mighty Heart” (June 22)

For some, the same questions that surrounded “United 93” last year surround “A Mighty Heart”: How real is too real? Angelina Jolie stars as Mariane Pearl, the widow of Daniel Pearl, the Wall Street Journal reporter who was abducted and beheaded in Pakistan in 2002. Directed by Michael Winterbottom — hardly a stranger to bleak topics but definitely a stranger to the Hollywood mainstream — the question is simpler: How well has he managed a big-budget, big-studio (Paramount) project, with one of the most sought-after actresses on the planet?

“Live Free or Die Hard” (June 27)

Terrorists, an abducted daughter, and a hapless police force — time for John McClane (Bruce Willis) to come to the rescue. In the fourth run through the gauntlet, Mr. Willis and comic relief Justin Long (the guy from those Mac ads) are pitted against Timothy Olyphant (“Deadwood”) in a story stitched together by Len Wiseman, the director behind “Underworld” who ordered substantial re-writes upon coming on to the project. We’ll see if those tweaks were worth the 12-year wait since “With a Vengeance.”

“Ratatouille” (June 29)

Another summer, another surefire Pixar megahit. This year, it’s “Ratatouille,” perhaps the hardest sell of the Pixar canon: A misfit rat (voiced by Patton Oswalt) with culinary dreams sets up shop in the kitchen of a high-end Paris restaurant. Will audiences want to spend two hours immersed in a rodent world? Given the director (Brad Bird, of “The Incredibles” fame) and the company (Pixar, which managed last year to make a blockbuster out of a comedy about bland, barely animated cars), it should be a sure thing.

“Rescue Dawn” (July 4)

On Independence Day, this much-delayed Werner Herzog jungle epic will offer one of the most intense military POW escapes ever put to film. Based on the story of U.S. Navy pilot Dieter Dengler (who Mr. Herzog already profiled in his acclaimed 1998 documentary “Little Dieter Needs To Fly”), his escape after six months of torture in a Laotian POW camp, and his improbable survival in the jungle while awaiting rescue, “Dawn” pairs Mr. Herzog’s intense storytelling with the considerable acting talents of a resolute Christian Bale as Mr. Dengler and a frayed Steve Zahn as the captive’s imprisoned comrade.

Here’s the only day this summer when the blockbuster crowd and the art house crowd will find themselves buying the same tickets.

“Transformers” (July 6)

What started as an apparent joke has, thanks to an online trailer that has become a sensation, emerged as one of the summer’s most anticipated, big-budget action spectacles. “Transformers,” based on the popular cartoon series (and, for some of us, all those action figures), is not coming to the movie theater as a fluffy cartoon, but as a live-action film about a mysterious robotic alien race that crashlands on earth with the aim of battling for its power source.

“Harry Potter and the Order of the Phoenix” (July 13)

In the fourth “Potter” installment, a struggle for power is under way at Hogwarts, just as Harry is targeted by Wizard authorities. As things fall apart, the threat of Lord Voldemort’s return ups the ante. Who needs descriptions, you already know if you’re going.

“The Simpsons Movie” (July 27)

Being produced in almost complete secrecy, the much-discussed “Simpsons Movie” arrives mere weeks after the iconic show airs its 400th episode. After years of fans requesting a big-budget version, the question now is whether die-hards, who may have drifted from the show during recent years, will come back to buy an opening-weekend movie ticket. Reports of substantial changes to the film following an unsuccessful West Coast focus group don’t bode well …

“The Bourne Ultimatum” (August 3)

In the most successful espionage franchise of the last few years, director Paul Greengrass (who scored last year with “United 93”), screenwriter Tony Gilroy, and star Matt Damon return with another chapter in the story of an amnesiac spy. Jason Bourne is getting closer to discovering the truth about his identity as he unravels the truth behind a top-secret spy-training program — a discovery that, big surprise, makes him the target of a professional assassin.

“The Ten” (August 3)

There’s a sizable contingent of die-hard “Stella” fans in New York City, particularly fans of David Wain, the leading creative force behind the comedy troupe’s holy grail: 2001’s “Wet Hot American Summer.” “The Ten” is a comedy that’s been making the festival circuit, starring “Knocked Up” costar Paul Rudd, Jessica Alba, and Winona Ryder, and featuring 10 vignettes inspired by the Commandments.