I lived with a benign ghost for several years. My parents bought their current house when I was three years old, and me and my brother were often in the room around the corner from the stairwell (no halls in the house) either as a shared bedroom or preferred playroom since it offered more floor space for toys. It was an almost daily occurrence for a shadow to walk through the room. And I don't mean along the well, it was as if a person was there, but transparent and featureless. He--it was male in appearance at least, broad shoulders and no breasts--would walk around the corner out of the stairwell, go past us (or around us if we were in the walking path it usually took) and walk through the door into the attic stairwell. We opened the door a few times to see if it went all the way up, but it had always disappeared by then.
I don't recall ever seeing him again after we remodeled the attic into another bedroom. My little sister uses that room now, and it's harder to substantiate her claims as a ghost, but she says she often hears breathing and her touch-lamp gets turned off every so often.
The house isn't without some current activity, too. A few years back, an apparition showed up that simply walks across the front porch. It's normally something you catch out of the corner of your eye. My mom first noted it because she always keeps half an eye out for when the mail comes (she works at home) and started getting faked out by swearing she saw the mailman go by but wouldn't find mail in the box. Shortly after this began, she learned that the old lady that owned the house before she did--who often drove by to see what kind of changes they were doing to the house, she specifically loved the bay window they put in the front--had died a few weeks ago. So, we call that particular apparition by her name.
EDIT: Worth adding, I chuckle a little at all the "they don't exist they can't exist don't ask me about it"-type posts people have added. Reminds me of my wife. She insists quite fiercely that there's no way ghosts can be real, but godamn if she didn't refuse to sleep upstairs at my parents' house for a few years because she didn't want risk seeing a ghost and being freaked out. For the record, she did see the porch apparition a few times and has a hilarious reaction each time once she realizes what just happened, and still insists 'we just overlooked things' when items are missing for a few hours before turning up on top of other items that had been moved while searching for it.
