Clark Griswold (Chevy Chase) is determined to have a “good old-fashioned family Christmas,’’ but Cousin Eddie (Randy Quaid) and a house full of wacky relatives don’t make it easy. Chase and Quaid are joined by fellow Saturday Night Live alumni Julia Louis-Dreyfus and Brian Doyle-Murray. Beverly D’Angelo is Clark’s always supportive wife, Ellen. (“We checked every bulb, didn’t we?”)