Star Trek: The Next Generation
I swear I didn't select episodes based on how bad they made Next Generation look, but "Rascals" is easily one of the most ridiculous episodes of the whole franchise. I mean, it makes "Spock's Brain" looks like "City on the Edge of Forever."
The basic premise has Picard, Guinan, Keiko O'Brien, and Ensign Ro de-aged to childhood because of a transporter accident. Seriously.
This doesn't even account for the wildly disparate adult ages they represent, certainly Picard and Guinan. (Maybe this doesn't matter given the premise. But still.) There's some mild amusement to the proceedings, including Riker pretending Kid Picard is his son when the inevitable additional crisis occurs (it only figures that the Ferengi are involved, I guess), but, I mean, seriously?
And, actually, this is also the final Next Generation episode I'll be writing about this month. Early in the month I also included "The Dauphin," which was a decent Wesley Crusher episode from the second season. Not as good as, say "The Game," but then, it had far less Ashley Judd in it. I also featured "Genesis," which featured the far more awesome physical alteration of the crew being devolved into various ancestral states. Fish Troi cannot be topped. Except by Lemur Picard...
(Okay, okay. Cake Troi obviously tops Fish Troi. Bonus points if you can tell me about the episode in which Cake Troi appears. And what kind of frosting she sports!)