(news.bbc.co.uk) - The Chronicles of Narnia: Prince Caspian took $56.6m (?29m) between Friday and Sunday to bump Iron Man off the top spot after two weeks.
Romantic comedy What Happens in Vegas, starring Cameron Diaz, took $13.9m (?7.1m) to hit the third spot.
Speed Racer, from Matrix masters Andy and Larry Wachowski, was fourth.
The big-budget anime-inspired film, starring Emile Hirsch and Christina Ricci, took $7.6m (?3.9m) in its second week.
Jeff Goldstein of the film's studio Warner Bros' said next weekend - which is Memorial Weekend in the US - was "do or die" for the film, which cost $120m (?61m) to make.
Motherhood comedy Baby Mama, starring Tina Fey and Amy Poehler, made $4.6m (?2.3m) to inch ahead of Patrick Dempsey's romantic comedy Made of Honor, which earned $4.5m.
Forgetting Sarah Marshall was in seventh with $2.5m (1.3m), followed by Harold and Kumar Escape from Guantanamo Bay with $1.8m (?0.9m).
Jackie Chan and Jet Li's martial arts movie The Forbidden Kingdom dropped a spot to ninth with $1m (?510,000).
Rounding out the top 10 is newcomer The Visitor with takings of $687,000 (?350,000).
The eagerly-anticipated Indiana Jones and the Kingdom of the Crystal Skull, which had its premiere at the Cannes Film Festival on Sunday, will open in cinemas in the US and Canada on Thursday.