Tomten är far till alla barnen (1999)

In what has to be one of the worst ideas in Christmas party planning history, Swedish house wife Sara decides to celebrate the yuletide season with her three ex-husbands and their families. Though her current spouse Janne initially is quite opposed, he eventually gives in. Then the booze kicks in. Families start infighting. Janne grows increasingly annoyed as the guests make repeated references to having sex with his wife. And during dinner, Sara announces that she is pregnant. This strikes Janne as odd considering that he had a vasectomy a year before. Soon the party devolves into utter chaos.