The Muppets Take Manhattan (1984): written by Tom Patchett, Jay Tarses, and Frank Oz; directed by Frank Oz; starring the voices of Jim Henson, Frank Oz, Dave Goetz, Steve Whitmire, Richard Hunt, and Jerry Nelson; and Juliana Donald (Jenny), Lonny Price (Ronnie Crawford), and Louis Zorich (Pete): Amiable third Muppets movie takes place in an alternate timeline from the first two. Or perhaps it's a movie made by the Muppets of the first two films, played so straight and non-meta that no one addresses the camera at any point.
As always, the Jim Henson Muppets are a fun and charming bunch. The film riffs on the old 'Let's put on a musical!' chestnut. It also sees all the Muppets graduate simultaneously from college at the beginning of the film. Clearly this is either Earth-2 or a fictional movie about the Muppets! (In)famous for introducing that blight The Muppet Babies on the world. Because it's not a non-fictional Muppet movie, any marriages performed seem to have been permanently treated as 'Out-of-Canon' afterwards. Recommended.