Unless incest, murder and serious family dysfunctions are your idea of high humor, you'll probably be better off saying no to "The House of Yes."

In fact, the film (adapted from Wendy MacLeod's odd stage play) has major problems aside from its unsavory themes — not the least of which is its weak premise.

Then there's also the fact that there are no sympathetic characters. Everyone in this highly distasteful dark comedy is dumb as a post, mentally disturbed or both.

To be fair, actress Parker Posey deserved the acting award she received from this year's Sundance Film Festival for her performance as Jackie-O, the film's lead character, a kooky, Kennedy-obsessed debutante. It's just unfortunate that the other cast members, and consequently the movie, aren't nearly as good as she is.

As the film opens, Jackie-O is primping for a Pascal family get-together — a happy occasion for her because Marty (Josh Hamilton), her estranged twin brother, is finally coming home to Washington, D.C. But Marty has a surprise for the family — he's engaged to a waitress, Lesly (Tori Spelling), whom he's brought back with him.

That little bombshell leaves dopey younger brother Anthony (Freddie Prinze Jr.) and Mrs. Pascal (Genevieve Bujold), the humorless family matriarch, reeling. And then there's the recently de-institutionalized Jackie-O, who becomes even more unhinged with that revelation.

But wouldn't you know, the power blacks out. And as the lights go out, some long-held family secrets come to light, not the least of which is the incestuous relationship Marty and Jackie-O once carried on. (The twins actually "renew" their bonds while intoxicated and a shocked Lesly finds herself bedding down with Anthony.)

There's so much in the way of foreshadowing through the film that if audiences can't figure out what's coming, they must not be paying attention (and that might not be such a bad idea).

But as mentioned, Posey displays astonishing range here, playing a character who's sexy, funny, caustic, bitter and hysterical — sometimes all at the same time. None of the others, however, seem even remotely inspired. Spelling is every bit as vacuous as you'd expect, while Prinze displays a Keanu Reeves-like woodenness.

Of course, it doesn't help that director Mark Waters does nothing to open up any of the scenes, and consequently, the movie feels like a filmed stage production.

"The House of Yes" is rated R for profanity, violence, sex and some vulgar jokes and references.