Star Trek turns 50 years old this week, proving that the final frontier can last a long time if enough people want to keep visiting. But beyond the original series, with its glorious pastel colors and triumpharate of Kirk, Spock and McCoy, there have been no less than five other TV Star Treks to enjoy over the last half century. That’s a lot to catch up with, so we’ve made it easy, choosing a best, and not-so-best episode of each for you to sample, so you know just what’s out there. Just be warned: for a franchise that’s lasted five decades, the lows are really impressively low.

The animated Star Trek series that aired from 1973 to 1974 was the first sign that Trek wasn’t like other shows—featuring the majority of the original cast (Pity poor Walter Koening, who was missing this time around), and written by many of the same writers as the original show, it was far and above the quality of the average Saturday morning cartoon — a fact obvious from watching this episode, which takes Spock into the past to rescue his younger self from danger, as written by D.C. Fontana, the same writer that introduced Spock’s family in the original series.

Of course, not every episode was a winner. The flaw in this episode might be obvious from the title; after watching the crew of the Enterprise deal with threats to entire planets, their own history and existence itself on multiple occasions, who really cares about a practical joke or two, even if it includes the Romulans? Sometimes, the lowered stakes of the new format did come into play, sadly.

After two TV series and four movies, it was decided to try Star Trek on television again in the mid-1980s, leading to Star Trek: The Next Generation — arguably the most popular of any of the incarnations of the franchise to date, at least on the small screen. While hardcore fans would quibble about the best episode of the series was, the highlight in terms of excitement is probably the two-part “Best of Both Worlds,” which ended the show’s third year by kidnapping the show’s lead and turning him into a bad guy… and then started the fourth season by trying to working out how to defeat an unbeatable enemy.

By the time The Next Generation was winding up, the show was visibly running out of steam, as evidenced in this seventh season episode that sees android crew member Data suffer through horrific nightmares that include seeing the ship’s counselor turned into a cake. No, that’s not a typo; she’s a cake. And at the end of the episode, we get to see her get “revenge” by showing up with a Data cake! Oh, how we laughed. No, wait; I mean “winced.”

Star Trek: Deep Space Nine was the little Trek that could. Darker and more ambitious than the other series, it was unafraid to try things that were weird, off-kilter and distinctly un-Star Trek, whether it was an ongoing storyline that plunged the universe into an ugly war that left no side unscathed, or this one-off episode that focused on racism in 1950s America, as seen through the lens of an African-American sci-fi writer… who just happened to look exactly like the series’ lead.

Not all of DS9’s ideas worked out so well, though; this attempt to spice up an episode by turning the stakes of a seemingly harmless game particularly deadly, for example, just came across as gimmicky and unnecessary as it sounds, made all the worse by the repeated catchphrase of the playful aliens that gives this episode its title. Never mind moving along home; a better idea would be to move along to the next episode.

The premise behind Star Trek: Voyager was a simple one: a starship gets abandoned on the other side of the universe in unexplored space, and has to get home. Instead of exploring the final frontier, the issue for this series was instead surviving it. By far the best example of this was the trippy “Year of Hell” two-part storyline, in which things go from bad to worse for the crew of the eponymous Voyager, up to and including a near-total abandoning of the ship and a mutiny that doesn’t quite come off. How could the show come back after that? All it takes is one explosion…

Sometimes, the high concepts of Voyager seemed more silly than inventive, as in this episode where an experimental warp drive somehow rewrites the DNA of the ship’s pilot, turning him into a lizard man who kidnaps the Captain in order for the two of them to have lizard babies, and… yeah. Not exactly a winner, let’s put it that way.

The franchise returned to its roots—and beyond—for Enterprise, a show set at the beginning of humanity’s adventures into deep space. Lacking much in the way of a coherent vision for how to proceed, much of the show feels like reheated leftovers of earlier stories from other series, but “E2” (which introduces a second Enterprise from the show’s future that quickly comes into conflict with the regular ship) is just a good old fashioned mind-bender of a story, even if it lingers on the “technobabble” of explanatory dialogue a little bit too heavily.

If Enterprise—and indeed, Star Trek as a whole—has a blind spot, it’s the concept of sex. Sure, women wear skintight clothing and short skirts, but people actually enjoying a sexual relationship? It makes the collective writing crew blush, based on the evidence of the shows to date. Worse yet, when they try and demonstrate how cool with it they are, you get episodes like this embarrassment, which takes place on a “pleasure planet” seemingly designed by people who don’t understand what pleasure is actually like.