Before I went overseas I used to work at the Old Adelaide Inn on O'Connel St. For those that aren't familiar, it's a smallish cosy old style hotel with the Snooty Fox restaurant inside.
In my first couple of weeks there I was asked to look after the Prospect Rotary Club's weekly meeting in the upstairs function room. All went fine and eventually everyone left and I started to clean and reset the room for a function the next day. While I was picking up some glasses from a table I noticed what seemed to be an old man, hunched over slightly and wearing a white shirt, navy vest and grey pants in the right corner of my eye. I assumed it might have been a Rotary member who forgot a jacket or something, but when I turned to look face on, there was nothing there. I just laughed in my head thinking that I was just creeping myself being alone in an old hotel function room. Then when I started picking up glasses again I saw the same figure in the left corner of my eyes and once again it was not there when I turned to face it.
That freaked me out a little, but once I finished what I needed to do I headed downstairs. One of the other girls who had worked there for longer than me thanked me for doing a good job and without even mentioning my experience, she proceeded to explain how she doesn't go up there by herself because it is 'haunted'. Apparently she had never seen the 'ghost' but often heard 'him' making noise in the upstairs function kitchen and toilet when noone was around, she also named 'him' Bill.
The old night auditor who only ever worked overnight reception shifts was the longest serving employee and he also had his share of strange happenings in the hotel.
I don't believe in ghosts, but that one instance is the closest I've ever been to changing my mind on that.