I had an auditory hallucination a few days ago while waking up from a nap (no, there were no drugs involved, just sleep). My head felt like it was buzzing like it sometimes does while waking up from a very deep sleep only this time the buzzing grew and grew until suddenly I heard something like a small choir (mostly male voices) singing "Aaaaah" briefly, then something like a pop and the sound and the buzzing were gone. It was pretty neat. I'm chalking it up to "brains are weird that way".
Some time when I was much younger I once had a visual hallucination - also sleep-related, this time lack-thereof. I was driving home after a party (again no, no drugs involved) fighting the urge to fall asleep at the wheel when I saw one of those old-style bicycles with the huge front wheel dart out in front of me and disappear. Shortly after I saw a couple of flashing road barriers which also disappeared. I'm confident that none of these were real but you'll just have to take my word for it.
I have also suffered from phantom vibration syndrome, though not so much lately.