I posted a thread on this subject 'bout a month ago. Heh. Yeah, I believe... but that's through my personal experiences. I'll copy/paste them for your reading pleasure!
Basically, on a nightly basis... I could hear something going up and down the stairs. There's a little more to it than that, though. When the sounds of the creaking stairs would reach the top... I could hear breathing. Heavy breathing. And I'd hear a few creaks of the floor coming toward my room... the breathing getting louder... then fading away... and then the sound of something going down the stairs. Sometimes this would happen once a night, sometimes it'd happen continuously.
I thought I was being paranoid ... but then my brother mentioned to me that he'd heard it too. His room was right next to mine... and he was laying awake at night hearing the same shit I was. The stairwell was always ice cold... and my brother said he'd seen a black mass lurking on the landing several times. I never saw anything like it, though.
Other odd things would happen around the house too. I often felt like there was something watching me when I was in the kitchen... a 'heavy' sort of presence that seemed to lurk just behind me. In our cupboards, there were lots of plastic hooks to hang coffee cups on... but for some reason, they'd never stay on the hooks. I'd hang them all up and within an hour they would have 'fallen' off. The thing is, you have to physically lift them UP in order to get them off of the hooks... there was no way they were just sliding off.
That stuff really scared me at the time, but now that I think back on it... there really wasn't a reason for me to be scared. Never once did... whatever the fuck was there... bother me physically. It just seemed to be going about its business.
I think that way now because one of my closest friends is dealing with something REALLY scary in his house. It's unlike anything I ever experienced (or even heard of) before. I noticed it years ago... but was too afraid to say anything about it lest people think I'm even more crazy than I actually am. Recently I discovered that everyone that frequents the house (and there are a lot of us) has experienced SOMETHING weird... and not all of it is benign.