This happened to me about three years ago.
I was about sixteen years old at the time.
I don't remember the exact day or date that this took place on but I just know that it was in the evening.
My grandma was dropping me off at my house, where I was home alone that night. I think my mom was out of town or bowling that night, but I knew she was due back sometime that night and my two brothers were spending the night at my grandparents.
Anyways so my grandma dropped me off at home and she had one of my brothers with her, they left and I was in my room, which was on the higher level of the house. She commented on how they were going to a store before they drove the seven miles back to her house.
Some time later, about a half hour to an hour later I was sitting in my room when I heard movement and voices coming from downstairs. Thinking it was them stopping by after going to the store I ran downstairs but to my surprise no one was there. Shaking it off I walked back upstairs and continued to sit around in my room. I never went downstairs when I was home alone at this house.
About an hour or two later I heard footsteps downstairs again and muffled voices. Remembering what happened the last time I heard the footsteps and voices downstairs I walked over to the staircase and peeked down because I didn't want to freak myself out if no one was actually down there. From the staircase you can only see the doorway to the kitchen/dining room and part of the hallway.
I stood there for a minute or two just watching and waiting for someone (thinking it was possibly my mom back from wherever she was that night) but no one walked across the hall, my mom would usually always walk down the hall when she just got home. I shook it off again and just walked back into my room and sat in there until my mom got home.
I really don't know what happened that night but I know it wasn't floorboards creaking because the movements and voices were apparent.