Amid a summer of familiar franchises and bankable blockbusters, conventional Hollywood thinking received something of a readjustment this weekend, when three of the biggest sequels in the land lost the majority of their audiences during their second, third, and fifth weeks in release. In their place, a wild card emerged as the weekend’s big surprise.

By Sunday afternoon, box office analysts were marveling at the stunning drop-off in attendance for the third “Pirates of the Caribbean” film, which lost some 60% of its business in its second weekend in theaters (but still managed to win the weekend with a $43 million haul). Meanwhile, “Shrek the Third,” in its third weekend, dropped half its business, and “Spider-Man 3” seems all but dead, averaging less than $1,000 a screen, a day (or roughly 100 tickets for a day’s worth of showings). What does it all mean? That today’s typical shelf life for a major Hollywood blockbuster is shorter than ever.

The movie that made business headlines this past weekend was the one that giddily bucked the summer trends: “Knocked Up,” the Judd Apatow comedy that received near unanimous praise from critics on Friday and went on to beat out Mr. Apatow’s “The 40-Year-Old Virgin” with a three-day total of just under $30 million.

Averaging a whopping $3,300 a screen a day and finishing with the fifth-best R-rated comedy opening ever, “Knocked Up” didn’t just make back its filming budget this weekend, it did so with a formula that flies in the face of what’s been called the “Pirates’ philosophy” of blockbusters. For starters, “Knocked Up” is rated R, which means it shuns the 15-year-old boys that Hollywood so covets in favor of the 20- and 30-somethings who know a thing or two about the stresses of family, the struggles of marriage, and the shock (good or bad) of pregnancy. Second, it was not made with a franchise in mind, nor as an explosion-obsessed epic action-adventure, but as a stand-alone comedy that directly (and some might say bravely) addresses the polarizing issue of abortion.

Even more interesting, “Knocked Up” does not feature a single brand-name superstar. The film’s leading lady, Katherine Heigl, enjoys a modest following thanks to her role on ABC’s “Grey’s Anatomy,” but Seth Rogen, seen on posters and in trailers across the country, is by no means an A-list name or face, and is known primarily for his small, quirky supporting parts in “Anchorman,” “You, Me and Dupree,” and “The 40-Year-Old Virgin.” What’s more, Mr. Rogen, who gets writing credits on three forthcoming movies, doesn’t seem headed for marquee lights. He lacks Brad Pitt’s chiseled features, not to mention the abs, biceps, hair, and attire that typically go with them.

But this weekend’s box office numbers showed that audiences clearly were connecting with the curly haired would-be dad — so much so that business for “Knocked Up” jumped nearly 20% on Saturday, indicating a substantial word of mouth turnout. Sure enough, every screening of the film in the East Village on Saturday night (strangely, only a handful of theaters showed the film in Manhattan), was sold out, and not with crowds of raucous teenagers but with crowds of older, quieter audiences who seemed to appreciate the film’s precarious balance of the serious and the silly.

Given the final weekend tally for “Knocked Up” and the fact that it exceeded all expectations while still being smart, sophisticated, and starless, it seems movie studios don’t need a $300 million epic like “Pirates of the Caribbean,” or a star factory like “Ocean’s Thirteen” to win the opening weekend and then actually stick around for a few weeks.

They just need smart writing, equally smart characters, and a respect for the audience.

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Speaking of Mr. Pitt, long lines could be seen outside the Sunshine Cinema this weekend, as younger crowds set out to catch two midnight screenings of “Fight Club,” perhaps the most recent addition to the accepted list of modern cult classics. The movie, about a generation of men trapped in an emasculating era who try to break out of their numbing isolation by beating the crap out of one another, made plenty of waves back in 1999. But as a ubiquitous DVD, and a bankable title for any venue’s midnight movie schedule, it’s become an accepted Gen Y masterpiece and a smart choice for revival theaters.

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For those who may have missed “Fight Club,” two different film events across Manhattan this week focus on similar ideas of revolt and uprising. This afternoon, fans can catch the final installment of the “Magnum in Motion” series, hosted by the Film Society of Lincoln Center (filmlinc.com). Highlighting the works of photographers from the Magnum photo agency in honor of its 60th anniversary, the series’ final installment, “Pictures From a Revolution,” focuses on the Sandinista victory in Nicaragua and features one photographer’s return to the country a decade later in hopes of reuniting with those he photographed.

Also, beginning this coming Sunday, Charlie Chaplin’s 1936 masterpiece “Modern Times” will return to Symphony Space (symphonyspace.org) for sporadic screenings during the next two weeks. It doesn’t take a film scholar to note the movie’s scathing critique of the decimation of the workforce by the automated revolution and, by extension, the victory of bottom-line thinking over humanity.

While next weekend’s multiplex looks to be dominated by the silliness of “Surf’s Up,” the breeziness of “Ocean’s Thirteen,” and the sleaziness of “Hostel II,” “Modern Times” seems like the perfect reprieve from, well, modern times.