Star Trek, “Arena” (1967) A defining moment in the Star Trek pantheon. A defenseless Captain Kirk must fight Gorn, the reptilian captain of another ship. Tense from beginning to end, with the ever-resourceful Kirk pulling out his MacGyver bag of tricks, using the planet’s resources to make gunpowder and a gun. Guess who wins?
Star Trek, “Amok Time” (1967) A Vulcan wedding ritual forces Spock to fight Kirk to the death. The fight scene is perhaps more famous for its over-the-top music than for its choreography—Jim Carrey perfectly re-created it in The Cable Guy—and this is the only episode in which we remember Spock showing emotion (when he learns he didn’t actually kill Kirk).
Star Trek II: The Wrath of Khan (1982) The first showdown between archrivals Kirk and Khan (played by William Shatner and Ricardo Montalbán, a pair of Master Actors, Over-the-Top Class) is a suspenseful, riveting, sharply written and altogether fantastic moment of Star Trek genius. The visual effects may be a bit spotty, but the performances? Timeless.
Star Trek II: The Wrath of Khan (1982) The Kobayashi Maru story: In which we learn that cadet James Kirk cheated on Starfleet’s “no-win situation” test. “I don’t believe in the no-win scenario,” he tells his companions, marooned with him deep in a planet. Thus, sci-fi’s primary symbol of humankind’s vigor and indomitability reveals that he can’t stand to lose even a fictional brush with death—a necessary trait for exploring the universe. (Then he whips out his communicator and arranges a rescue, cheating death again.) This sequence gains added resonance later, when Spock sacrifices himself in another no-win scenario.
Star Trek: The Next Generation, “Yesterday’s Enterprise” (1990) A rift in space-time creates an alternate reality where Picard’s Enterprise-D is a battleship on the frontline of a losing war with the Klingons, thanks to the mysterious emergence of the Enterprise-C, a ship from the past. On its surface, the episode is an elaborate means to give us the return of the killed Tasha Yar (Denise Crosby); deeper, it’s an exploration of the nature of sacrifice.
Star Trek: The Next Generation, “Cause and Effect” (1992) A smartly written, hugely entertaining episode about the Enterprise being caught in a perpetual time loop that continually ends in the ship’s destruction. As the crew’s collective déjà vu slowly builds, each iteration has to find a way of communicating its plight to the “next” crew in order to break the loop.
Star Trek: The Next Generation, “Chain of Command” (1992) In contrast to Kirk, Picard was almost always reserved and proper as a captain. When captured and tortured by the Cardassians, though, he turns steely and defiant, resisting ever-more-painful techniques designed to break his perception of reality, stubbornly shouting “There are four lights!” instead of the five his captors want him to believe are there.
Star Trek: Deep Space Nine, “Trials and Tribble-ations” (1996) Poking fun at continuity issues and the franchise’s penchant for time travel (the DS9 crew goes back in time to interact with Kirk & Co. via special effects), this warm, funny episode of Trek’s most underrated series has plenty of highlights, perhaps the best of which is Worf’s horrified reaction to early Klingons, who lack the distinguishing head ridges. “We do not discuss it with outsiders,” he huffs.
Star Trek: First Contact (1996) Another intense Picard moment finds the typically composed captain exploding with rage at the relentless advances of the evil Borg, shouting “The line must be drawn here! This far and no further!” while pummeling the model ships in his office. Eventually Alfre Woodard’s pragmatic Lily Sloane calms him down, and he goes on to kick Borg ass.
Enterprise, “These Are the Voyages …” (2005) Granted, the final episode of Enterprise is kind of a lame cheat, focused more on Next Generation nostalgia than on the show itself. But the last shot of an episode that at the time seemed like it might have been the end of the franchise altogether, with Captains Kirk, Picard and Archer reciting the famous opening narration as their three different ships fly by, is a sweet and respectful valediction.