Favorite non-Trek characters played by Trek series regulars?

Nimoy as Paris in Mission Impossible.

Brian Thompson as the uber demon in Buffy

Dominic Keating as a watcher/guardian who gets turned into a vampire on Buffy

Colm Meany in The Button War and The Man Who Went Up a Hill...

(James Darren was also in T J Hooker)

I tried to just list ones not previously mentioned. There are so many...

 

How about Nimoy as that guy who goes "in search of" various ancient aliens and hidden creatures?

 

Oh, and Keiko in Joy Luck Club?

Patrick Stewart on the Simpsons as the head of the Masons--or whoever the heck they were.

It probably doesn't count because they were playing themselves, but the NG crew guesting on Family Guy when Stewie kidnaps them all.

 

Frakes and Spiner both had memorable appearances on Hill Street Blues.

 

I don't know if it's been mentioned yet. And I don't really like the show Hell on Wheels, but my family likes it. Colm Meany plays a character in it.

 

I forgot about Nana Visitor playing a doggie psychologist on Castle

 

Jason Isaacs as Jackson Brodie in Case Histories

 

Has Prof. X been mentioned yet?

 

Richard Herd (Adm. Paris) was also in TJ Hooker if memory serves.

 

Yep I mentioned him.

Jason

 

Patrick Stewart in Conspiracy Theory

 

Breaking the rules to mention a recurring character, but how about Andrew Robinson as the Scorpio Killer in the first Dirty Harry movie?

 

Brent spiner. The master of disguise , Out to sea,
Colm Meany . Con Air
Picard . Avery Bullock (American Dad)
Q . As the father of the jessys GF on the breaking bad

 

I found it mildly funny. A few real knee-kicker moments. But the porn angle was a bit overdone.

 

Dwight Schultz as Captain "Howling Mad" Murdock on the A-Team tv series.
Rene Auberjonois in a Night Gallery episode "Camera Obscura" .

 

Rene Auberjonois in Fallout: New Vegas.

 

During Season 7, IIRC. I think that's why it's often a body double under the umpire mask in 'Take Me Out to the Holosuite'.

 

I can't believe no one has mentioned John Laroquette and Brent Spiner on Night Court.
Nanak Visitor also had a memorable role as a woman suffering from multiple personalities who took Dan Fielding hostage.

 

I have improbably fond memories of De Kelley in Night of the Lepus. As always, he presented a questionable script with utter sincerity. (It probably didn't hurt that I had a crush on him when the movie came out.)