Our entire family has been plagued by a ghost of some sort for awhile, because it seem almost impossible to fall down the stairs, even if you start to, you're always able to stop. However, if you go up the stairs at least 45% of the time you trip! Sometimes I go up the stairs and I KNOW I've cleared the stair and after that thought, I trip up the stairs! That was before my father's uncle committed suicide in our garage. It still happens but now other things happen.
There are times when you'll feel watched when you're playing on the computer. You will feel it then it will go away. Even if you turn around nothing is there. Also behind the computer on the wall, if the light is on you sometimes see a shadow go across. Personally I have seen a "shadow man" in our giant upstairs window, he was really dark against a white wall, I saw him in the window. He stood there then turned the corner and left. I jumped up and turned the corner as well, the man didn't run and I did, if he was there I would have seen him, I didn't see him.
Once my cat was sitting on a chair when the screen door flew open, he went out, I closed the door and went to tell my father. When I got back the cat was inside and the door was open again. My father's uncle loved cats, I could see him letting them in and out. Once, my mother told the ghosts to leave, for awhile nothing happened, then one day the screen door flew open and my dad said "Come in" we've noticed them again.