Seeing Jon Favreau and Vince Vaughn reunite on the big screen is an enticing proposition. As anyone who has watched them in The Break-Up or Made can attest, the two Swingers alums seem to step up their improv game whenever they share the frame, and their verbal sparring rarely yields anything short of comedy gold. The above certainly holds true in Couples Retreat, the new relationship comedy directed by child actor-turned-filmmaker Peter Billingsley. Sadly, the demands of the film's bloated ensemble cast and the constraints of its PG-13 rating allow precious few opportunities for Favreau and Vaughn to work their magic. And since the rest of Couples Retreat's main castmembers refuse to pick up the slack when they're on screen, the end result is uneven disappointment.

The plot of Couples Retreat centers on four couples who travel to Bora Bora for a new-age "tune-up" for their flagging relationships. Each pair has its own unique set of problems: Jason (Jason Bateman) and Cynthia (Kristen Bell) are type-A achievers whose perfect union is threatened by their inability to conceive; Joey (Favreau) and Lucy (Kristin Davis) have essentially lived a sham marriage since an unplanned pregnancy led to their shotgun wedding 18 years ago; Dave (Vaughn) and Ronnie (Malin Akerman) are so tied up in the day-to-day routine of their busy lives that the passion has vanished from their relationship; and recently dumped Shane (Faizon Love) is dealing with the pain of his break-up by shacking up with Trudy (Kali Hawk), a shrieking sexpot half his age. It's a solid lineup of actors, to be sure. Problem is, everyone has to have their own jokes, their own story arc and their own tidy resolution at the end. But save for a few amusing moments, nobody besides Favreau and Vaughn is particularly funny or interesting.

If anything, it's the supporting actors -- including Frenchman Jean Reno as the blissed-out seminar guru, Peter Serafinowicz as the satin-voiced group guide and Carlos Ponce as the groping yoga instructor -- who provide the bulk of the laughs. The whole experience of Couples Retreat ultimately feels like it was phoned-in by everyone involved, as if it were a scheme concocted to get a free, all-expenses-paid vacation in Bora Bora. Most disappointing of the bunch is Bateman, who is coming dangerously close to typecasting himself as the uptight, deadpan good guy. Dude needs to make a movie in which he kills someone -- or at least beats them very badly. Who's going to want to see an Arrested Development movie if Bateman essentially plays Michael Bluth in every movie he makes? Hollywood.com rated this film 2 stars.-Thomas Leupp.