I get a world tilting thing maybe once a year. Usually while falling asleep. I also sometimes get this weird perceptual thing where objects look huge, again, normally while in a dark room. I've also had odd sensations that accompany these perceptual changes.

All of these occur very rarely. Like I said, maybe twice a year, but closer to once per year. I can't find it now, but I had learned about seizure activity and how you can experience one without really knowing it, things just might get wonky like your perception, feelings, smells, etc.