I've only watched 40% of these... maybe putting this list together…
In this wacky military spoof, Lemmon plays a terminally bored Army private waging a war of wits as he tries to throw a party under the nose of his obnoxious commanding officer.
This is a delightful movie. I'm surprised it isn't better known.
The premise is that a group of GIs in postwar France want to throw a ball, but their humorless officer (Ernie Kovacs) is against it. So Hogan (Jack Lemmon), the ultimate fixer, finds a way around this grump.
The plot is nicely complex, with several angles and subplots complicating the action. The cast is superb. Lemmon is just outstanding as the guy who can talk his way out of every situation. Ernie Kovacs is equally good as the hardnose who is just one or two steps behind Lemmon. (This movie makes you wish for more Lemmon-Kovacs films. They would have been great together in "The Odd Couple.")
The service comedy subgenre has largely been forgotten in recent years, but "Operation Mad Ball" is an outstanding example. The next time someone says there were no good comedies in the Fifties, they should look at this one.