'Ender's Game' tops box office

This image released by Summit Entertainment shows Asa Butterfield, left, and Harrison Ford in a scene from "Ender's Game." (AP/Summit Entertainment)

LOS ANGELES – Weekend moviegoers chose sci-fi over slapstick.

"Ender's Game" scored the No. 1 slot at the weekend box office, earning $28 million in its opening weekend and sending "Jackass Presents: Bad Grandpa" into second place, according to studio estimates Sunday.

Lionsgate's "Ender's Game," based on the novel by Orson Scott Card, stars Asa Butterfield and Harrison Ford as intergalactic soldiers.

Comments made by Card expressing opposition to gay marriage led some to call for a boycott of the film. But a strong first-place opening met the studio's pre-weekend expectations.

However, ticket sales didn't come close to the opening weekends of other young-adult science-fiction adaptations such as "Twilight" and "The Hunger Games." It did fare better than "Beautiful Creatures" and "The Mortal Instruments: City of Bones."

A representative for Lionsgate declined to be interviewed for this story.

Paramount's candid-camera comedy starring Johnny Knoxville disguised as an old man brought in another $20.5 million in its second weekend, with a domestic total reaching more than $62 million.

Other films opening this weekend didn't generate as much enthusiasm.

CBS Films' "Last Vegas," featuring an all-star cast of silver screen veterans including Michael Douglas, Robert De Niro, Morgan Freeman and Kevin Kline, opened in third place, with $16.5 million.

Relativity Media's 3-D animated kiddie flick "Free Birds," with characters voiced by Owen Wilson, Woody Harrelson and Amy Poehler, debuted in the fourth spot, with $16.2 million.

After its fifth weekend at the box office, the Warner Bros. 3-D stunner "Gravity" is still holding in the fifth position. It banked $13.1 million over the weekend, bringing its domestic total to $220 million.

Overseas, Disney's "Thor: The Dark World" earned an impressive $109.4 million in its first international weekend. The Marvel superhero sequel opens domestically next weekend.

Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Rentrak. Where available, latest international numbers for Friday through Sunday are also included. Final domestic figures will be released Monday.

1. "Ender's Game," $28 million.

2. "Jackass Presents: Bad Grandpa," $20.5 million.

3. "Last Vegas," $16.5 million.

4. "Free Birds," $16.2 million.

5. "Gravity," $13.1 million.

6. "Captain Phillips," $8.5 million.

7. "12 Years a Slave," $4.6 million.

8. "Cloudy with a Chance of Meatballs 2," $4.2 million.

9. "Carrie," $3.4 million.

10. "The Counselor," $2.3 million.