The Ben Stiller comedy about making a movie about the Vietnam War grossed an estimated $11.5 million.
A new movie, "Babylon A.D.," a futuristic action thriller starring Vin Diesel and Michelle Yeoh, took the No. 2 spot with estimated ticket sales of $9.7 million.
The Batman flick "The Dark Knight" moved back up to No. 3 from fourth place with an $8.75 million weekend, bringing its seven-week total to $502.4 million. "The House Bunny" slipped from second to fourth at $8.3 million.
"Traitor," an international conspiracy drama starring Don Cheadle, debuted at No. 5 with $7.9 million, followed by "Death Race," down three spots with $6.23 million.
Another new offering, "Disaster Movie," a comedy about -- what else? -- disasters befalling a group of young people, featuring Matt Lanter and Vanessa Minnillo, checked in at No. 7 with $6.17 million.
Filling out the top tier were "Mamma Mia!" at $4.42 million, "Pineapple Express" at $3.39 million and "Vicky Cristina Barcelona," which moved back up from 11th at $3 million.
"Star Wars: The Clone Wars," fell out of the Top 10 all the way from fifth last week. "Mirrors" and "The Mummy: Tomb of the Dragon Emperor" also were banished.