I figured there'd be some overlap between MSPA and Firesign, but searches get me two hits, one's not what I'm looking for, the other's buried deep within an archived thread.
Not a big surprise, it's surprisngly hard to find people who are into esoteric radio comedies from the '60s.
The Firesign Theatre is four (or five) crazy guys performing densely layered radio dramas. They're still around, but sadly many of the master recordings have been lost and the vinyl releases are hard to come-by.
Anywho, I'm testing the waters here. I'm a noob as the post count can attest, so I figurered I'd post here with this.
A search on Youtube will turn up some of their better known and later work. "Nick Danger" will turn up some great radio-detective parodies that if you squint your ears at just right, will resemble Problem Sleuth.