I don't think I have ever actually seen a ghost, but we have had some really unexplainable stuff happen at my house before we moved out. Also, I should note, the people who owned the house before us, told us that when they bought it, the house had absolutely nothing in it, no cabinets, no toilets, the tub was gone, everything, just the walls. Apparently gypsies lived in the house before them.
My mom is in the military, so she travels a lot, one night she was packing her bags and packed some books to read on the flight. The next morning, my mom left and my dad was cleaning up their room, then left for work. When he came home, one of her books was on her nightstand that wasn't there when he left.
Another time, we had a clock on the wall of our dining room, it was hung up on the wall with one of those sort of key shaped holes, where you put a screw in the wall and pull it into the slot. So you have to actually lift up on this clock to get it off the wall. Well one day this clock managed to fall off the wall, the screw was still there, and our dog sat next to this clock for a good hour and barked at it before any of us found the clock was off the wall ( the dog liked to bark, a lot, so we didn't go look right away. )
The last time I remember happened in my parents room again, they claimed one night the door on my moms nightstand ( I think that damn thing was haunted ) Ripped off and flew across the room. I wasn't home for this one, so I can't say really.
Oh, and once my brother claimed he had heard crying in the basement, but could only hear it while he was playing tom sawyer on rock band...
I also remember I used to see a weird black cat a lot, but that was generally after 24hr gaming runs.
TL;DR:
-House Owned By Gypsies
-Mysterious Book
-Evil Flying Clock
-Nightstand From Hell
-My Brother Is An Artard