Four Midwestern couples travel to an island paradise for a little fun in the sun, although the trip’s planners, Cynthia and Jason (Kristen Bell, Jason Bateman), are also using the getaway as a shot at salvaging their marriage.  The vacation also serves as a relationship wakeup call to Dave and Ronnie (Vince Vaughn, Malin Akerman) who take their union for granted, and Joey and Lucy (Jon Favreau, Kristin Davis), high school sweethearts who have completely lost that spark and wile away their days in bitterness. Faizon Love, who worked with Vaughn and Favreau on Made, is the recently divorced Shane, a middle aged guy who is dating a much younger and more energetic Trudy (newcomer Kali Hawk, who’s a riot btw).  Throw in a self-help, yoga obsessed guru named Marcel (The Professional’s Jean Reno) and a stick in the mud resort leader (Peter Serafinowicz) and one has the right amount ingredients for a lively enough comedy.  Vaughn and Favreau wrote the film with Dana Fox (What Happens in Vegas), and like Swingers and Made, Couples Retreat contains finely etched and, at times, hilarious characters. Peter Billingsley, who’s produced with Vaughn and Favreau over the years, does an able job as a director, and the supporting players all have their chances to shine in the film. Although the movie has its share of dick, poop, and sex jokes, most of it works.  It’s also a joy to see Favreau, now an A-list director, remind audiences that he cut his showbiz teeth as a first rate comedian (he also did scene stealing work in Four Christmases and I Love You, Man).  After Swingers, Vaughn was tabbed by Hollywood as the next great leading man, and for a while he tried to fit in that mold (The Locusts, Return to Paradise, Clay Pigeons, The Lost World: Jurassic Park).  But being a top banana is his forte (although he did a welcome dramatic turn with Into the Wild), and Couples Retreat is another highpoint in his resume.  Also, yoga fans should watch out for Carlos Ponce, a yoga instructor who puts the couples to their limits with his blatant sexual overtures and his all too revealing speedo. The yuks are aplenty in Couples Retreat, and one hopes Favreau and Vaughn have a few more stories up their sleeve.