"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.