The movie pulled in $35.3 million to take over the No. 1 spot from "Zombieland," the horror comedy that slipped to second place with $15 million.
"Couples Retreat" features "Swingers" co-stars Vaughn and Favreau in the tale of four couples at an island therapy resort.
The micro-budgeted fright flick "Paranormal Activity" did big business in its first full weekend after two weeks of midnight-only screenings. "Paranormal Activity" came in at No. 4 with $7.1 million in just 160 cinemas, a fraction of the theater count for other top releases.
The movie was shot for just $15,000.