The House of Yes (1997)

Thanksgiving certainly brings out the worst in families although the Pascal clan is dysfunction personified. Marty (Hamilton) brings home fiancee Lesley (Spelling) to meet his eccentric mom (Bujold) and siblings. Younger brother Anthony's (Prinze) a dropout with no direction and Marty's twin sister Jackie-O (Parker) is bonkers. She's recreated herself as Jackie Kennedy Onassis and has had a very intimate relationship with Marty that Lesley probably doesn't know about.