I was hearing a tune in my head and thought "maybe this is my auditory imagination pattern matching the same way my vision system does with random splotches beneath my eyelids", and I listened, and noticed there did indeed seem to be a sound I was ignoring, but my pattern recognizer wasn't, that resembled the tune that kept playing in my head.

It also occurs to me that my sense of where my body is, and having a body for that matter, is probably also pattern matching and model building based on tactile senses along with proprioception and whatnot.. Which is maybe why my body can feel differently positioned in a dream, since my limbs are likely numb, and the signals coming to the brain about them are probably easy to interpret any which way..