On Thanksgiving eve, Jackie-O's eyes glisten as she tells her twin brother's fiancee, "I've been over the edge, now I'm back." She washes her anti-psychotic medication down with rum, noting that the pills are color-coordinated with her eyes. Surveying the goings-on, Jackie-O's mother excuses herself, saying, "I'm going to baste the turkey and hide the kitchen knives."

Welcome to "The House Of Yes," Mark Water's brilliant black comedy adapted from Wendy MacLeod's macabre play. "The House Of Yes" is a jewel, one of those rare and exhilarating films that completely realizes its own unique vision.

The privileged Pascal family inhabits a decaying Washington DC mansion, insulated from the rules of the outside world. Marty (Josh Hamilton) is the only family member to leave home since his father disappeared on the day John F. Kennedy was killed. When the young man returns with his fiancee, a Donut King hostess named Lesly (Tori Spelling), he hopes to introduce a little normality to the home. Nice try, Marty. His otherworldly mother (Genevieve Bujold) takes Lesly into the kitchen for a little chat, casually informing her that "Jackie was holding Marty's penis when they came out of the womb." After a storm knocks the lights out and Mom retires to her room, we learn more about the kids. Jackie-O (Parker Posey) and Marty have been lovers for years, reenacting the Kennedy assassination as foreplay.

You see, Jackie-O has this thing about the Kennedy's, routinely donning a pink suit, pearls and a pill box hat to emulate the former First Lady. While Jackie-O frantically tries to draw Marty back into her arms, Lesly's time is occupied by the twins' shy, eager-to-please younger brother Anthony (Freddie Prinze Jr.), who spills the beans about his siblings' romance, then wheedles Lesly to help him lose his virginity. Just to be fair, you should know that after this mundane stuff has been established, things get a little weird.

"The House Of Yes" has a delightfully creepy feel. It's like finally finding out what the Addams Family REALLY did behind closed doors. The whole thing could easily have become campy, smug or just too damn precious, but Waters' manages the mean trick of keeping this story emotionally grounded. By directing the actors playing the Pascal family to maintain a sense of heightened reality, he highlights just how isolated the Pascals are. With their mansion serving as some plush sensory deprivation tank, the family is cut off from life, damned by their own lack of self-restraint to live a hollow existence of melodrama and role-playing.

Water's couldn't have pulled this film off without skilled actors, and the cast of "House Of Yes" is superb. You'll immediately notice Parker Posey's triumphant turn as the whacked-out Jackie-O, but pay attention to the other performances as well. Genevieve Bujold creates a matriarch who is regal, snobby, droll and distracted in a truly odd, disturbing fashion. Josh Hamilton is a perfect yang to Jackie-O's yin. Watch his face when she tries to convince him to drop his attempts at a traditional life and return to the loony bed. Hamilton conveys a stunning transition of attitude using only his eyes and subtle changes in facial expression. He is exceptional. Tori Spelling conveys a charming naivete as a simple girl who "smells like powdered donuts." The real scene stealer, though, is Freddie Prinze Jr., who initially appears to be merely an ancillary character, but comes into his own with a sly, remarkably skilled performance. Watch him closely during Anthony's attempted seduction of Leslie. This boy can ACT.

While adroitly mixing humor and horror, Waters' plays games with your head. When Jackie-O begs Marty for some Dallas motorcade sex, you find yourself hoping he will agree. When Anthony tries to bed his brother's fiancee, you hope that he'll succeed. Is Waters trying to make a case for incest and stealing your brother's girl? Of course not. He is taking the audience, isolated in a movie theater, and showing us how easy it is to be seduced into wrong thinking by attractive, charming people while we're cut off from the rest of the world. Just like the Pascals.

At least that's my spin on it. Part of the beauty of "The House Of Yes" is that there are infinite ways to interpret the material. As the film makes its way across the country, it's proving to be one of those love-it- or-hate-it movies. That's the way it usually works with innovative films, and "The House Of Yes" is certainly innovative. Shocking in its originality, it is funny, frightening, thought-provoking and one of the years best films.