I've had a few ghost encounters in my life but this one is the easiest to share. In Copehnagen I was couch-surfing on a 3rd floor flat. The roommates told me the building was haunted. At exactly 1:30 every night you could hear someone walking all the way up the 4 floors in the stairwell then all the way back down and the door would slam. I heard it every night that I was still awake. The steps had a distinct limp which was noticeable and also interesting how the door would slam. That door had a hydraulic on it- it couldn't be slammed like that if you tried. The roommates cautioned me not to open the door to look as this would "upset him" and then they would find their things go missing. After 'upsetting him' in the past, they found their wallet in the VCR, the remote in the freezer- things like that. So I never peeked.
Then one night we had another couch surfer. Up at 1:30, he hear the limping step and asked about it. I said "That's the ghost" and as I said the word 'ghost' our front door FLEW open and the footsteps stopped. It was so freaky.