The in-laws (1979)

With his daughter about to marry, Manhattan dentist Sheldon Kornpett is getting in over his head. The groom's father Vince Ricardo (who may/may not be CIA) has been in over his head so long he may have lost it totally.

As played by Alan Arkin and Peter Falk, they're as different as night and day—and one of the funniest screen teams ever as The In-Laws.

Throw in a uniquely zany script by Andrew Bergman (Blazing Saddles, Fletch) and snappy direction by Arthur Hiller and you have a wild and woolly comedy that doesn't stop at hilarious. The In-Laws is a scream.