Just finished watching 'The Ensigns of Command' on the TNG S3 Blu-Ray set. Fantastic episode.
One little thing that caught my attention. At the end of the episode, Data stuns the five guards positioned in front of the aquaduct, and later we see the central guard struggle back to his feet after the confrontation has ended.
I believe this guard was actually Skipp Sudduth, better known as 'Sully' from Third Watch and who also had a small role in the movie 'Ronin'.
It was only a small, non-speaking role on the TNG epsidoe, but it looked a lot like Skipp. I looked up the credits on the net and the five guards were played by uncredited stuntmen.
I believe this would fit in with the time when Skipp was starting out on television, and getting a role as an extra would be a logical place to start out.
It's only a trivial matter but it caught my interest when viewing the episode.