He said these kids like Doctor Who, and, as much as I like that show myself, I also took this to mean they are fairly immune to boredom.I don't know. "The Man Trap" has nice scary bits, but there's a lot of mushy stuff with Nancy Crater that might bore small children. And you don't really see the monster until the end.
"Tribbles," of course, is a natural.

But I take back what I said, and second your suggestion. That episode has everything - Klingons and a Klingon ship, the Enterprise, a space station, a fist fight, and little lovable plush fuzzballs.

P.S. I just experienced that surreal moment when you're replying to someone online and simultaneously get an email from Amazon suggesting you buy a book... by the person you're talking to. LOL.