One possible episode would be
March 21, 1954 where Jack listens to "The mean old man" radio show. Mostly because it opens with something that describes Jack's character to a "T": It sounds like a woman renter chewing him out for being too cheap, but it turns out that he's only listening to a radio show. (Interesting "theatrer of the mind" discussion, perhaps.) However, we find out later that the "Mean Old Man" show is based on the experiences of one of Jack's renters.
One drawback, (or advantage, depending on your point of view,) is that very few of the more colorful characters show up in this episode: No racetrack tout, no Phil Harris, no Mr. Kitzel. That might be an advantage to the first-time listener. (fewer back-stories to deal with.)
It does have something the students might relate to, though. Mel Blanc makes an appearance early in the show. Another plus is that Dennis's song is very accessable to a modern ear. ("Hey, Brother, Pour the wine.")
If you want to drop names, try an episode with Harry Shearer (of "The Simpsons" fame) as a boy from the Beverly Hills Beavers club. (
"Going to the Beach" comes to mind.)
or, as Shimp said, check out any Christmas shopping episode!
here's a
radio Christmas episode.