Special Guest Star ...

In what was probably the most absurd guest star ever, Joe Piscopo on ST:TNG.*

There was also James Doohan, DeForest Kelly, and Leonard Nimoy on ST:TNG.

Hans Conreid on one the better episodes of Lost in Space. Michael J. Pollard was also memorable as a guest on the show; Pollard also appeared on the original Star Trek’s “Miri.”

*Data wanted to learn how to be funny, so he had the holodeck manufacture a famous comedian. And of all the great comics in all of history, the one he chose was Joe Piscopo. :rolleyes:

OK, not sci-fi, but it does have geek credibility; Jasper Johns on the Simpsons. He got to say “Yoink!”

I hope I didn’t inadvertently suggest that these all need to be sci-fi. I’m open to any good suggestions, and y’all have been giving great ones. Keep 'em coming!

Stanley Adams, who played Cyrano Jones on “Star Trek” and a Carrot on “Lost in Space.”

Danny Thomas as the alien on The Dick Van Dyke Show (which was a Danny Thomas Production).
I think he just wanted a way to be a Guest Star without being Danny Thomas.

And, obviously, I forgot that I mentioned sci-fi/fantasy/horror in the OP. :smack:

But, really, I’m open to any good suggestions.

Joe Namath on The Brady Bunch

Nancy Reagan on Different Strokes
Not really a special guest star but soon to be stars like

Tom Hanks on Family Ties

George Clooney on The Facts of Life (am I remembering that right?)

Leo DiCaprio on that stupid show with Alan Thick and that who is now the crazy banana guy. now.

David Warner in Babylon 5

I’m all about David Warner in sci-fi/fantasy. The man was Jack the Ripper, Sark and Satan (sorry - “Evil Genius”), fercryinoutloud. And apparently he’s going to be in a Doctor Who episode. Wahey!

Michael Berryman as the Devil in two episodes of Highway to Heaven.

Thereby proving that David Warner is the ultimate bad guy. When you get to be in a movie with the guy who was Alex de Large and you get to be the bad guy?

That’s serious, yo.

Peter Boyle in the X-Files episode “Clyde Bruckman’s Final Repose”.

Robin Williams on Law and Order:SVU, Homicide, and Friends
Helen Hayes on Hawaii Five-O
Goucho Marx on The Bill Cosby Show*

Richard Burton and Elizabeth Taylor on The Lucy Show
Rod Serling on The Jack Benny Show and The Red Skelton Show

*(The short-lived variety show that was his second show, if you ignore I Spy)

Ooooo! And George Reeves (as Superman, IIRC) on I Love Lucy!

Dick Clark, Colonel Klink as well as all the bad guys in Batman.

How about some Hey It’s That Guys from short-lived 80s sci-fi tv series:

Buck Henry in Quark.

Ray Walston in Otherworld.

Both Kurtwood Smith and Ray Wise (Clarence Boddicker and Leon Nash from Robocop) were in the Blue Thunder tv show.

Nixon on Laugh-In.

“The Muppet Show”: Mummenschanz, Vincent Price, Christopher Reeve, etc.

Vincent D’Onofrio in Homicide
John Cleese in Cheers
Any of the murderers in Columbo.

If I recall correctly, Rod Serling also narrated The Undersea World of Jacques Cousteau from time to time. Hardly a “guest star” role like the others listed, but I always found it interesting.

“The A Team”: Hulk Hogan and Boy George.