Cameos you think no one knows about.

Bit players as troops.

[QUOTE=Wikipedia]
Other cameos in the film include directors Terry Gilliam, Sam Raimi, Costa-Gavras and Joel Coen, musician B. B. King, and visual effects pioneer Ray Harryhausen.
[/QUOTE]

I am just now finishing watching The Wire. As a former Baltimoron, I have enjoyed seeing familiar city sights and recognizing a few bit players. Here are a couple that may have slipped by a lot of people.

There was an episode where the mayor went to Annapolis to see the governor to beg for money. There was a security guard at the State House who had a few lines, and I enjoyed recognizing that it was the then governor of Maryland, Bob Ehrlich, playing the guard.

In the final season, which focuses on the newspaper, I noticed David Simon’s wife, Laura Lippman, playing a reporter.

Remembering that I linked to the Wikipedia article, I am well aware that these other directors appeared in the film. However the only one I recognized when I saw the movie some thirty years ago was Frank Oz. (Joel Coen wasn’t nearly as famous back then, having done only a few movies and I wasn’t very familiar with the others either.)

There’s lots of local celebrity cameos in Portlandia, but the most famous would probably be former mayor Sam Adams, who played in-show mayor Kyle MacLachlan’s assistant.

Into the Night, directed by John Landis has to hold a record. Most people can spot a few of the cameos, but all of them?

*John Landis appears in the film himself as the mute member of the quartet of Iranian henchmen, alongside:

Jack Arnold, director of science fiction films, including It Came from Outer Space (1953), as the man with the dog in the elevator.
Rick Baker, Academy Award-winning make-up artist on An American Werewolf in London (1981), as the drug dealer.
Paul Bartel, director of low-budget films, including Eating Raoul (1982), as Beverly Wilshire Hotel Doorman.
David Cronenberg, director of body horror films, including Shivers (1975) and Rabid (1977), as Ed's supervisor in the boardroom.
Jonathan Demme, who at the time had directed a number of lower-budget and exploitation films, as the thin federal agent with glasses.
Richard Franklin, Australian director of Roadgames (1981), as the aerospace engineer sitting next to Herb in the cafeteria.
Carl Gottlieb, who co-wrote Jaws (1975), as the large federal agent with moustache.
Amy Heckerling, director of Fast Times at Ridgemont High (1982), as "Amy", the clumsy waitress.
Jim Henson, creator of The Muppets, as the man on the phone talking to 'Bernie'.
Colin Higgins, who wrote Harold and Maude (1971) and directed The Best Little Whorehouse in Texas (1982), as the actor in the hostage film.
Lawrence Kasdan, writer and director of Body Heat (1981), as the police detective who interrogates Bud.
Jonathan Lynn, co-writer of Yes, Minister, as the tailor who fits the SAVAK agents.
Paul Mazursky, director of Bob & Carol & Ted & Alice (1969) and An Unmarried Woman (1978) as Bud Herman, the beachhouse owner and accused drug dealer.
Carl Perkins, rockabilly musician and composer of 'Blue Suede Shoes', as Mr. Williams.
Daniel Petrie, director of A Raisin in the Sun (1961), as the director of the hostage film.
Dedee Pfeiffer, actress and sister of Michelle Pfeiffer, as the hooker.
Waldo Salt, Academy Award-winning screenwriter of Midnight Cowboy (1969) and Coming Home (1978), as the derelict who informs Ed of his car having been towed.
Don Siegel, director of Invasion of the Body Snatchers (1956) and Dirty Harry (1971), as the man caught with a girl in the hotel bathroom.
Jake Steinfeld has a small role as "Larry," Jack Caper's bodyguard.
Roger Vadim, director of And God Created Woman (1956) and Barbarella (1968), as Monsieur Melville, the French kidnapper.*

-per wiki

Similarly, Joseph Cotten was an extra in the crowd in Touch of Evil. He was visiting the set and Orson Welles had him take part, and the camera did linger on him.

Marlene Dietrich also had a small uncredited role in the film. Word has it that the studio executives were surprised to see her on the screen, since they had no idea she was on the set. Zsa Zsa Gabor was credited, even though the had next to no screen time. Eva Gabor, OTOH, had about the same amount of screen time, but was uncredited. In addition, Oscar winner (at the time) Mercedes McCambridge also had a small uncredited role.