Short version: All CDs of ZBS audio productions are now available at half price! If you like Welcome to Night Vale, you might like ZBS's stuff.
My first encounter with The Fourth Tower of Inverness was on cassette, in high school or college. It was a radio drama, created in 1972, the first in the series of The Adventures of Jack Flanders. As Wikipedia notes, it “combines elements of Americana and Old-time radio with metaphysical concepts such as past life regression, Sufi wisdom, Tibetan Buddhism and shamanistic communication with the natural world.” It's over seven hours long, in 7-minute and 30-minute episodes. There is nothing else quite like it.
...Except for other radio and audio pieces by ZBS Productions. They've been doing this for forty years now; there are a couple dozen Jack Flanders adventures, and a lot of other stuff as well.
In particular, the other thing ZBS is probably best known for is a series of adventures of Ruby: Galactic Gumshoe. Each storyline consists of a bunch of short punchy episodes, about three minutes long; some funny, some serious. Blasters, aliens, a hard-boiled detective, metaphysics, and such supporting characters as the Peter Lorre-like Rodant Kapoor. Episodes are occasionally interspersed with funny and pointed spoken-word explorations of various topics by a pair of androids known as the Android Sisters. It looks like there've been about nine adventures so far. In Ruby 2, the protagonist is named Ruby Too. In Ruby 3, Ruby is back, along with a techno-anthropologist named Inanna who's on a quest to the Underworld. And so on.
You can listen to the first three-minute episode of the first Ruby story for free online: “Here's a Kiss for You.” Transcription of a couple lines of that:
My name is Ruby. I'm a galactic gumshoe. A good one. The time is the 21st century; the planet is Summa Nulla, crossroads of the galaxy.
I don't love everything I've heard of ZBS's material, and I haven't heard any of their new stuff in probably twenty years. The sheer quantity of material is a little intimidating at this point. But if you like audio drama, this half-price CD sale is a great opportunity to try out ZBS's stuff.
And it turns out that ZBS has been busy all this time; there are several other series I've never heard of available from their site. For example: Lady Windermere's Brass Fantabulous “is set in an alternative Victorian reality where most mechanical things are steam driven, including brass & cast iron robots. This series is a satirical comment on how governments create misinformation to justify their own often nefarious commercial interests, besides manipulating the gullible minds of their own people.” And the Anne Manx series (possibly not created by ZBS? I'm not sure) features Claudia Christian and Patricia Tallman of Babylon 5.
Most or all of their work is also available for purchase in MP3 format, but those recordings are not half-price; the discount applies only to the CDs.
One last thing: As I hinted up at the top of this post, I kinda think Night Vale is a sort of spiritual descendant of ZBS's work. It's not really the same thing; ZBS tends to go more for comedy, mystical metaphysics, and old-radio tropes, while the little I've heard of Night Vale tends to be more focused on a sort of mysterious surrealism. But I have a vague idea that Jack Flanders and Ruby might scratch some of the same itches.