I’m home alone. I was in my office working, and a few minutes ago I heard an absolutely clear sound like someone shaking beads in a small plastic container — three times, shake shake shake — from the adjacent living room, just outside my office door. It was too loud, clear, and specific too ignore. My nervous system cannot figure out what to do with this information, and keeps telling me that there must be someone in the apartment with me — triple-shaking beads! Oooh! WEEEEEIRD. Auditory hallucination? What the hell? Bit of a thing!
Update 2013: I’ve thought about this many times since. I’ve never thought there was a comfortable explanation for it. Also, I had a sort of related, funny experience.