Four couples come to a tropical resort and find themselves in the throes of intensive marriage-repair therapy. Imagine a half-assed update of Fantasy Island, somehow at once shriveled to short-sitcom proportions and bloated to feature-film length. The director is Peter “still-just-the-kid-from-A-Christmas-Story” Billingsley. The stars are Vince Vaughn and Jon Favreau (who wrote the script together, with Dana Fox), Jason Bateman, Faizon Love, Kristin Davis, Malin Akerman, Kristen Bell and Kali Hawk. Among the plot points, in addition to some boilerplate romantic recriminations, are a shark attack, a Guitar Hero showdown and a general sense of Vaughn and Favreau coming to terms with not being in Swingers anymore. Even still, Couples Retreat gives off a mild air of self-satisfaction, apparently the natural result of good pals having a good time in a good place making a movie that’s just not good.