I would nominate A Guide for the Married Man in that category. Starred Walter Matthau and Robert Morse, with cameos by Lucille Ball, Jack Benny, Sid Caesar, Art Carney, Wally Cox, Jayne Mansfield, Terry-Thomas, and others. Directed by Gene Kelly. Should've been a slam dunk, but it is the biggest misfire I've ever seen.
Great call. I saw this in downtown Chicago when it came out (my classmates hung out at Old Orchard Shopping Mall but I would head downtown to see first run movies.) I kind of enjoyed it, but then I was barely a teenager. I've never been able to watch more than five minutes of it since then. It is truly a horrible and offensive movie.