The closest analogy I can think of with listening to Firesign Theatre is catching a radio broadcast from a parallel universe. Their weird, layered tales of sound and fury project the feeling of being allowed a glimpse into another world, another culture, a warped version of our own with people that operate under alien logic and a completely different perception. This is a world where everything is normal to the inhabitants but foreign and nearly incomprehensible to an external eavesdropper - sort of like a shipwrecked Englishman trying to comprehend the language and rituals of the tribesmen on the south pacific island he's been stranded on.