I have two stories. Both of these experiences happened years ago, in my house.
My brother and I were home alone. We were playing cards and listening to music in our parents bedroom, when I started to hear our stairs creaking and thought someone was coming up our stairs(we live on the 2nd floor). I turned off the stereo and listened. The creaking seemed to go on forever, like someone was coming up, but not reaching the door yet. I told my brother to go see who it is, but when he opened the door there was no one. When he returned the creaking started again.
It was late at night, in the summer. At that time we had only one air conditioner, so we all slept in one room. Our door(which the stairs lead to) was locked and we had no guests. It was just us, my parents, my brother and I. I was lying in bed awake when I heard the door slam. I thought everyone was asleep so I said nothing. I thought that maybe I had imagined hearing it. The next afternoon when we were eating lunch my brother asked if anyone else heard the door slam. I know it wasn't my brother or my parents who slammed it, because we were all in the same room.
I can't say for sure if this house is haunted, but I know I heard those sounds which I can't explain and they scared the hell outta me.