This is the second encounter I had in my old house. It happened when I was roughly 13-years-old. I was living with my father and older sister at the time. My sister and I had separate rooms as dad and his fiancée had split up years before and her and her son had moved out.
Every night I would go to bed between 7pm and 8pm. If I had a lot of homework to do, usually I would sit up in bed and get some done before going to bed, other times it was straight to bed.
Every night at exactly 9pm I would hear a BANG on my bedroom window. Thinking it was one of the other kids on my street playing games, I chose to ignore it. When months later it was still happening and causing a lot of sleepless nights and cranky mornings, I decided it was about time I told my dad so we could try and get to the bottom of it. So that is exactly what I did.
Dad decided one night that he would be sneaky and hide under the house so he could jump out and serve it to who ever it was doing this. (The front of our house where the bedrooms were located was built up off the ground as it was on a slight hill. The space underneath was big enough for an adult to walk around slightly hunched over.)
After hiding under the house and waiting, sure enough 9pm came and so did the bang, but there was no one around. Dad tried hiding in different places on different nights, but every time came up with the same result, a big bang but nothing to explain it.
The scariest thing about this is that all bedrooms were right next to each other but no one else would hear the bangs except me, unless they were outside when it came. There was never an animal or a person to be seen.
I can't say this was a ghost or any kind of paranormal entity, but at the same time, without proof of it being a human or an animal, what else could it of been?