Something a little different. Listening to but also watching one of my two favorite episodes of Star Trek "Enterprise." My absolute favorite would be "Similitude," a very poignant tome, also the favorite of actor John Billingsley, who played Dr. Phlox.
But my close second would be "Carbon Creek" (season 2, episode 2), which is what I'm watching again tonight. Not really a time-travel episode, but merely an "old story you never knew," type episode. A throwback story, and one well conceived.
Given that my model railroading interests are also of the throwback variety, probably not that much of a surprise.
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As far as favorite series (a question that also comes up when discussing Star Trek), mine would actually be "Voyager."
And as I've said before, here and elsewhere, "I can tell you why Voyager is my favorite in just three words. And two of them are numbers...."