William Goldman's famous "Nobody knows anything" line? Still true.

On a weekend in which acclaimed filmmaker Jon Favreau sprung an entirely new -- and by most accounts, solid -- sci-fi concept on a box office that could certainly use one, only to watch it bomb, a retread adaptation of a 50-year-old kids property with gawd-awful reviews blew the blue paint off its pre-release tracking.

Picked to win the weekend box office, Favreau's "Cowboys and Aliens" underperformed even soft pre-release predictions Friday, grossing just $13 million, according to studio estimates. The $163 million film is on pace for only around $36 million this weekend, while the giant, throbbing collective brain of the tracking services called for an opening more like in the 40s.

Meanwhile, Sony's "The Smurfs" grossed $13.3 million -- and an A grade from "how'd you like the movie you just saw" research service Cinemascore. It's also on pace for around $36 million, but trackers foresaw an opening more along the lines of $30 million for the $110 million CG/live-action hybrid.

Yep, "Smurfs" is a hit ... even though critics collectively scored it at 18 percent on Rotten Tomatoes -- not that your 8-year-old really cares what Alonso Duralde thinks of the 3D.

One other film opened widely Friday -- Warner's "Crazy, Stupid, Love," an ensemble PG-13 comedy led by Steve Carell, Ryan Gosling and Julianne Moore, grossed a solid $6.6 million and should match the high side of its pre-release forecast at around $20 million.

As for holdovers, Marvel/Paramount's "Captain America: The First Avenger" grossed around $8 million Friday -- a drop of around 60 percent from its weekend-winning debut.

It'll finish the weekend with around $120 million after two weeks. And the eighth Harry Potter film will probably add just over $20 million to its three-week-old bounty and cross $300 million domestically.

Perhaps it's proof that the summer box office is no country for new ideas.

Updated, Friday, 4 p.m.:

Universal's "Cowboys & Aliens" grossed just more than $700,000 in midnight showings at 1,200 locations Friday, according to early studio estimates. This is small showing compared to some of the bigger summer movies. Not springing from an established franchise, the film does not have the sort of built-in fan base that generally drives midnight showings.

Earlier:

Sensing his genre-blending movie would be a tough sell to moviegoers during a summer rife with established film brands, filmmaker Jon Favreau has stumped for months, all across the country, in support of Universal's "Cowboys & Aliens."

But it seems certain that, despite Favreau's extensive campaigning for the $163 million film, it won't do big business at the weekend box office.

Also read: 'Cowboys & Aliens': Yeah, There Are Cowboys ... and Aliens -- But Not Much Else

Various box office watchers predict that the PG-13-rated film, which was executive produced by Steven Spielberg, stars Daniel Craig, Harrison Ford and Olivia Wilde, and opens up in 3,750 locations in the U.S. and Canada, will only premiere to around $40 million-$45 million this weekend.

Amid a summer in which even moribund superhero movies like "The Green Hornet" are opening to more than $50 million, that doesn't seem like such a great start.

Also opening widely this weekend, Sony Pictures 3D-CG take on Belgian-created cartoon figures The Smurfs will open up in 3,395 domestic theaters, with various prognostications putting the $110 million film's opening at more than $30 million.

Also read: 'Smurfs': Cheesy Reboot Will Annoy & Disgust Audiences of All Ages

Also, Warner will debut Steve Carell comedy "Crazy, Stupid, Love" in 3,020 theaters, with expectations hovering around the mid-teens for the $45 million PG-rated film.
Also read: 'Crazy Stupid Love': Needs More Crazy, Less Stupid, Much Less Gooey

Limited debuts this weekend include Joe Cornish's acclaimed sci-fi film "Attack the Block," with Sony launching it in eight theaters.

Lionsgate will start Dominic Cooper drama "The Devil's Double" off in five locations.

And Magnolia will premiere Jay Baruchel comedy-thriller "Good Neighbors" in two theaters.

Also, Marvel/Paramount's "Captain America: The First Avenger" will remain a factor at the weekend box office, with second-weekend projections falling in the $30 million range.

The big story, however, is "Cowboys & Aliens," Universal's bold attempt to render an orignal, if mashed up, concept on a summer box office repetitively rife with comic-book movies and series sequels.

Favreau started stumping for the film early. As the Los Angeles Times reported in early February, he was even jetting into small Iowa towns, along with "Cowboys" producer Ron Howard, film reels in hand, trying to seed buzz for the movie.

At Comic-Con last weekend, Favreau seemed to have culminated his big campaign in high style, with the movie's key demographic constituency giving the filmmaker and the cast a warm applause after the world premiere of the film.

But the movie hasn't found much traction with critics, who were giving it a collective 44 percent fresh score on Rotten Tomatoes.

Across all four key audience groups, meanwhile, total awareness of the film only hovers at around 85 percent, according to research firm NRG -- a good number would be in the 90s.

While the reviews for "Cowboys & Aliens" are hardly solid, they're a lot better than those of "The Smurfs," which have moved up from a conspicuously flat 0 on Rotten Tomatoes to total around 9 pecent fresh.

Noted TheWrap film critic Alonso Duralde: "It does for children's entertainment what lead paint does for children's toys."

Ouch.

As for "Crazy, Stupid, Love," the ensemble-casted comedy -- which stars Ryan Gosling, Julianne Moore and Emma Stone alongside Carell -- is scoring a strong 72 percent fresh on Rotten Tomatoes.

Possibly signaling an over-performance for the Dan Fogelman-penned comedy: From "The 40 Year Old Virgin" to "Evan Almighty" to "Get Smart" to "Date Night" to "Dinner With Schmucks," Carell has not headlined a big-budget comedy yet that's opened to less than $20 million.

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