UPDATE 1-'Meatballs' rolls to No. 1 at box office

* "Meatballs" grosses $30.1 million in North America

* "The Informant!" below expectations at No. 2

* Jennifer Aniston, Megan Fox movies also disappoint (Adds details throughout)

LOS ANGELES, Sept 20 (Reuters) - "Cloudy With a Chance of Meatballs," a new 3D animated feature based on a popular children's book, shone brightest at the weekend box office in North America on Sunday, overshadowing flops starring Matt Damon, Jennifer Aniston and Megan Fox.

"Meatballs" earned an estimated $30.1 million during the three days since it opened on Friday, said Sony Pictures Animation, a unit of Sony Corp (6758.T) (SNE.N). Industry forecasters were looking for the film to open in the $25 million-$30 million range.

The film is based on the 1978 book by Judi and Ron Barrett, in which a nerdy outcast invents a device that sends hamburgers, pizzas and pancakes dropping from the heavens. The voice cast includes Bill Hader, Anna Faris and Neil Patrick Harris, the host of Sunday's Primetime Emmy Awards.

"It's visually spectacular, but more importantly it's very funny and just like an amusement park ride," said Rory Bruer, president of worldwide distribution at Sony.

The film cost about $90 million to make, he said. It also opened at No. 1 in Britain and Mexico, although sales data were not available.

Meanwhile, Damon and Aniston suffered their worst openings in years with "The Informant!" and "Love Happens," respectively. "Jennifer's Body," the headlining debut of "Transformers" hottie Fox, was dead on arrival.

'INFORMANT!' MUTED

"The Informant!" -- a Steven Soderbergh-directed comedy-drama based on the true story of a mentally disturbed government informant played by Damon -- opened at No. 2 with $10.5 million. Warner Bros., a unit of Time Warner Inc (TWX.N), had hoped the well-reviewed movie would open in the low-teen millions, but noted that it cost just $20 million to make.

Damon's previous low was the $9.9 million start for his Christmas 2006 release "The Good Shepherd," which went on to earn $60 million.

"Love Happens," a romantic drama pairing Aniston with Aaron Eckhart," was No. 4 with $8.5 million. The $18 million picture was released by Universal Pictures. The General Electric Co (GE.N)-owned studio said the opening was in line with its expectations. As with Warner Bros., it hedged its bets by sharing the cost with an independent financier. Critics ripped the movie.

Aniston had been on a roll with such hits as "Marley and Me" and "The Break Up," which both opened with more than $30 million. Her latest effort is her worst since the $3.5 million bow of her Christmas 2005 romantic comedy "Rumor Has It."

"Jennifer's Body," a horror-comedy starring Fox as a cannibalistic high-school girl, followed at No. 5 with $6.8 million. It had been expected to open at No. 2 in the mid-teen range. The $16 million film was released by 20th Century Fox, a unit of News Corp (NWSA.O). Karyn Kusama ("Girlfight") directed from a script by Oscar-winning "Juno" writer Diablo Cody.

Last weekend's champ, Tyler Perry's "I Can Do Bad All By Myself," claimed the No. 3 spot with $10.1 million. Its 10-day haul stands at $37.9 million. The film was released by Lionsgate, a unit of Lions Gate Entertainment Corp (LGF.N).

"Inglourious Basterds" has become Quentin Tarantino's biggest film, both domestically and internationally.

The World War Two revenge fantasy fell four places to No. 7 with $3.6 million in North America, taking its five-week tally to $109.9 million. His previous best was the $108 million haul for 1994's "Pulp Fiction."

Its international total stands at $115.7 million after an $11.2 million weekend bolstered by No. 1 openings in Israel, Lebanon and Spain. Until now, his best foreign performer had been "Kill Bill, Vol. 1," which made $111.4 million in 2003.

"Basterds" was released in North America by closely held Weinstein Co, and internationaly by Universal Pictures. (Editing by Todd Eastham) (Los Angeles bureau +1 213-380-2014))