"Ender's Game" ruled the box office game on Friday night, topping all the competition with a strong $9.9. million opening day.  

The Gavin Hood-directed sci-fi film should earn around $28 million for the weekend, which is a strong, but not spectacular start for the controversial film. "Ender's Game," adapted from Orson Scott Card's seminal novel about futuristic pre-teen war games, stars Asa Butterfield, Harrison Ford, Ben Kingsley and Hailee Steinfeld. 

Last week's No. 1, "Jackass Presents: Bad Grandpa," was bumped down one spot, with the Johnny Knoxville comedy pulling in another $6 million. Its domestic total stands at $47.6 million, a hefty sum compared to its reported $15 million budget, but nowhere near the profits earned by the "Jackass" movies. 

Newcomer "Last Vegas" gambled its way to No. 3 with winnings of $5.1 million. The comedy features a cast of aging stars, including Robert De Niro, Michael Douglas, Morgan Freeman and Kevin Kline. 

Relativity's animated adventure "Free Birds" flew off with a disappointing $4 million. The film features the voices of Owen Wilson, Amy Poehler and Woody Harrelson, and cost a reported $55 million to produce.

"Birds" and "Vegas" will likely compete for third place over the weekend, and will earn around $15 million each. 

"Gravity" floated in at No. 5, earning another $3.6 million. So far, the space drama starring George Clooney and Sandra Bullock and directed by Alfonso Cuaron, has earned a stellar  $209 million.

Look for complete box office estimates for the weekend on Sunday.

Dave Lewis has been a Los Angeles-based entertainment writer and editor for nearly ten years. Originally hailing from Minneapolis, he moved to L.A. in 1996 to attend USC, before working for various periodicals and web sites including a lengthy stint at Variety.com. He joined the HitFix staff in 2011.