Although the four central couples go through many ups and downs over the course of the movie, ultimately the story is very pro-marriage/commitment. None of the couples has a "perfect" relationship, and they all have to put in real effort to make their partnerships succeed.
Dave gets splashed with a bloody bucket of chum and may have been nipped by a small shark (but the scene is funny, not scary). In another comedic bit, a rainstorm tips a couple out of their canoe, and they have to be saved by their friends. In an early scene, Dave trains his bedside gun on a suspected intruder.
Lots of jokes (verbal and visual) about adultery, masturbation, erections/"happy endings," and several very lewd yoga positions (complete with suggestive thrusting). A man's erection is clearly outlined under a sheet. Couples make out passionately and are shown in bed together, but there aren't any full-fledged sex scenes. Two shots of partial nudity -- one played for laughs (a characterdoesn't wear boxers, so when he's asked to strip down to his underwear,the audience sees his naked rear) and one that's more about ogling a dripping wet man -- but no sensitive body parts shown. Lots of skimpy bathing suits and beach wear, as well as some sensuous dancing and massage.
Although there are no F-bombs, there are plenty of uses of "s--t," "a--hole," "bitch," and derivatives of those words, as well as "hell," "damn," "hump," "twatting" (used in place of "tweeting"), "balls," "screw," "oh my God," etc.
Apple computers and Guitar Hero are shown frequently, with the video game gettng mentioned as part of Dave's work and even played during a fairly long scene. Also mentions of Froot Loops, PowerPoint, Sandals Resorts, and Applebee's; charaters drink Budweiser.
Adults on vacations drink (wine, beer, hard liquor/mixed drinks) and get tipsy/drunk pretty frequently, especially once they all go to the singles resort, where people are doing body shots and more. A 20-year-old character (who's the most avid partier of the bunch) has booze poured directly into her mouth at one point.