Like most of the other stories I read on this site mine is not too unlike the others with "weird and unexplained" happenings...
These two seperate experiences happened to both my mother and brother.
One night at my old family house, which I never really felt quite at ease in, my brother was alone watching TV. All of a sudden there was a loud bang from the upstairs which he described as sounding like a safe being dropped. As can be expected my brother freaked and ran out of the house in just his undershorts and stood under the streetlight.
Eventually, he had to go back inside and decided to be brave and went upstairs to check out the disturbance.
As expected, when the lights were turned on nothing was out of place or disturbed to account for that caliber of noise. Needless to say, he never slept upstairs again after that incident.
On another occasion, my mom heard the same noise, although it spooked her in a different way as she thought someone might be breaking into the house, this time she called me to investigate.
I promptly went over and very uneasily went up the stairs to the room where my brother as well as mother heard this loud bang.
As you can imagine, I was very, very scared as I have also had numerous experiences in this house and to this day I still get a bad feeling when even thinking about it.
I checked out the whole upstairs and found nothing out of place, the windows were closed and nothing outside could account for a noise like that outside of the house, besides why would it sound like it was coming from upstairs?
Another incident happened to my brother, a bit more disturbing though.
One night he was dozing off on the couch in the living room with all the lights off except for the streetlight shining into the living room. He woke up for no reason and felt compelled to look into the kitchen that was adjacent to the dining room. The kitchen light was off but he could definitely see a darker outline, like a black figure peeking around the door into the dining room. My brother blew it off and tried to sleep. When he was awoken again later on he looked up at the living room doorway and the black figure that he had seen before the kitchen was right at the living room doorway where he was. He freaked and turned on the lights.
To this day he sleeps with the lights on even though he has been out of my Mom's house.
I realize these experiences may not sound too scary to you, but hearing them from my family freaked me out.
I also have had some rather frightening experiences in that house myself, but my story would be too long.