I am not sure about this. If you stare at anything for long enough you get peculiar effects in your vision (try it).
That said, in the last year or so I have begun to enjoy music from the extractor fan in our kitchen. Each time it is on I hear a random genre of music - plain chant, brass band, jazz, etc. I don't experience it in any other context (or any other hallucinations before you ask). Anyone else get something like this?