I'm a spiritual and somewhat crazy person, and have been taught both zen and samatha meditation, though I rarely practice either.
I just underwent a series of short micros sleeps, which were accompanied by musical hypnagogic hallucinations. I've had both experiences many times, but never together - and it was the closest thing I can imagine to the "sound of one hand clapping".
I felt sleepier, stopped fighting, right after I closed my eyes would hear someone singing, and then immediately seem to wake up again. This process repeated itself some four or five times, until I stopped being amazed by it (see the first paragraph) and just fell asleep (- until now).
Do any sleep experiences, like hypnagogic hallucinations, micro sleeps, or even sleep paralysis, or anything else, have anything to do with meditation? It strikes me as one way that science might come to terms with the states associated with meditation.