It's been several years since I've seen this film (which I watched for a French class in college), so this is less of a review of a film and more of a suggestion to watch said film.
Title: Le Dîner de Cons (The Dinner Game)
Starring: Thierry Lhermitte, Jacques Villeret
Plot: Pierre and his group of friends host a dinner party every week to which each man invites a total stranger. This sounds like a nice gesture, but, in actuality, these dinners are a chance for them to humiliate people they think are ridiculous--men with strange hobbies or habits or people who are just plain stupid. Pierre plans on bringing François, a man he is sure will take the prize at the next "dîner de cons." But things don't go as planned when Pierre throws his back out and his wife leaves him and the only person around to help him is François. Soon Pierre is bombarded by crazy mistresses, possible tax audits, and a whole host of other problems as François' attempts to help only make things worse.
What makes the film really great, however, is the chemistry between Pierre and François. There's tension there because a) Pierre is in a lot of pain (both physically and emotionally) and François keeps making it worse and b) sweet, stupid François doesn't understand what he's doing wrong and keeps trying to make it up to a man he thinks is his friend. Throughout the film, Pierre comes to see his mistakes in life because they are laid bare to him by someone he thinks is a complete moron. It gives the story a soul that other comedies are lacking.
Why You Should Watch It in French: Obviously it's up to you if you watch it in French with subtitles or just watch an English dub. There's one joke, however, that I think works much better in French than in English. François accidentally calls Pierre's mistress, Marlène, whom Pierre has been attempting to cut out of his life...but he knows none of this. When he gets off the phone he tells Pierre that he's been talking to his sister. Pierre, who doesn't have a sister, is confused. When he informs François of this fact, the man insists the woman said that she was his sister. Pierre suddenly realizes what happened. Marlène's last name is Hissister. At least, in the English version it is. In the French version her name is Sasseur, which sounds like "sa soeur," which is French for "his sister." To me, Hissister is a crap last name and the joke loses some of its appeal because it's so obvious. In the French version, it's more subtle and it's funnier that François makes that mistake. In the English dub, it just comes off as being a weak attempt at being funny.
What About That Other Version?: Okay, so apparently America has to ruin everything foreign and this film is no exception. In 2010, a film called Dinner for Schmucks came out, starring Paul Rudd and Steve Carell, which is supposed to be a reboot of sorts. I've heard that it's absolutely awful and if you've seen it, don't let it keep you from watching Le Dîner de Cons. Personally, I haven't watched the atrociousness that is Schmucks, but I'm assuring you that Cons is a film you won't regret seeing.