and the winner for most cameos is:
It's A Mad, Mad, Mad, Mad World with 51 camoes:
* Jim Backus as boozy airplane owner Tyler Fitzgerald
* Jack Benny as a man who drives by in a Maxwell, offering to help
* Paul Birch as a policeman
* Ben Blue as the biplane pilot
* Joe E. Brown as the union official
* Alan Carney as a police sergeant
* Chick Chandler as detective outside of Chinese laundry
* Barrie Chase as Sylvester's love interest
* John Clarke as helicopter pilot
* Stanley Clements as squad room detective
* Lloyd Corrigan as the mayor of Santa Rosita
* Howard Da Silva as airport official
* Andy Devine as the sheriff
* Selma Diamond (voice only) as Ginger Culpepper
* Minta Durfee as a crowd extra
* Roy Engel as patrolman
* Norman Fell as a detective
* James Flavin as patrolman
* Stan Freberg as a deputy sheriff
* Nicholas Georgiade as detective
* Louise Glenn (voice only) as Billie Sue Culpepper
* Leo Gorcey as a cab driver
* Don C. Harvey as policeman
* Sterling Holloway as the fire chief
* Edward Everett Horton as Mr. Dinckler, owner of the hardware store
* Allen Jenkins as police officer
* Marvin Kaplan as garage man Irwin
* Robert Karnes as Officer Simmy
* Buster Keaton as Jimmy the Crook (boatman)
* Tom Kennedy as the traffic cop
* Don Knotts as the nervous motorist
* Charles Lane as the airport manager
* Harry Lauter as police dispatcher
* Ben Lessy as George the steward
* Bobo Lewis as pilot's wife
* Jerry Lewis as the man who runs over Culpepper's hat
* Mike Mazurki as the miner bringing medicine to his wife
* Charles McGraw as Lt. Matthews
* Cliff Norton as a reporter
* Barbara Pepper as a crowd extra
* ZaSu Pitts as Gertie the switchboard operator
* Carl Reiner as the tower controller
* Madlyn Rhue as Secretary Schwartz
* Roy Roberts as a policeman
* Eddie Ryder as air traffic control tower staffer
* Arnold Stang as garage man Ray
* Nick Stewart as migrant truck driver
* The Three Stooges (Curly Joe, Moe, and Larry)[2] as airport firemen
* Sammee Tong as a laundryman
* Doodles Weaver as a hardware store employee
* Jesse White as an air traffic controller
and of course:
Main characters
* Edie Adams as Monica Crump, wife of Melville Crump
* Milton Berle as edible seaweed company owner J. Russell Finch
* Sid Caesar as dentist Melville Crump (a role originally meant for Ernie Kovacs before his death in a car accident)
* Buddy Hackett as comedy writer Benjy Benjamin
* Ethel Merman as Mrs. Marcus, mother-in-law of J. Russell Finch and a very cranky woman
* Dorothy Provine as Emeline Marcus-Finch, wife of J. Russell Finch
* Mickey Rooney as comedy writer Dingy 'Ding' Bell
* Dick Shawn as Sylvester Marcus, Mrs. Marcus' son and Emeline's brother
* Phil Silvers as the out-of-work piano player Otto Meyer
* Terry-Thomas as Lt. Col. J. Algernon Hawthorne
* Spencer Tracy as Captain C. G. Culpeper
* Jonathan Winters as truck driver Lennie Pike
[edit] Secondary characters
* Eddie 'Rochester' Anderson as a cab driver
* William Demarest as Santa Rosita's chief of police (Aloysius)
* Jimmy Durante as Smiler Grogan
* Peter Falk as a cab driver
* Paul Ford as Col. Wilberforce