My Grandma and Grandad lived in a house that is only about eighty years old, and so when I was little, it hadn't had anybody die within the house. When I was about five or six, I was playing in the smallest bedroom there with my walkie-talkies (if you don't know what they are then they're like a mobile phone, but you can only communicate with the other handset of the pair- they operate on a frequency unique to the set, so that no other signal should be picked up). Now, I was attempting to see if I could hear my voice in the other handset when I spoke into the one i had in my hand, and the other handset was at the other side of the room (remember, I was only six). Then, I heard a voice from the handset I was holding- it was saying "Guess who it is now, guess who it is..." and it continued to tell me to guess. At only six you wouldn't have thought I would have been that frightened, but I was absolutely terrified and switched the walkie-talkies off and never used them again. My grandad dismissed this as just picking up another radio signal, but I believe that it was something else.
Also in my grandma's house I keep smelling cigarette smoke, and neither of my grandparents are smokers. It's really strong, but generally disappears after a few seconds. I sometimes smell roses too, but that is fainter. I didn't mention this to anyone but then I heard my grandma sniffing one day and she told me that she could often smell cigarette smoke in the house! I then told her I could too, and she told me that she thought it was my great-great grandad who smoked "like a chimney" up until the day he died, watching the house. I told her about the roses and she said she could smell them sometimes, but not as often as the smoke.
Anyway, in 2007 my grandad died in December in the house. He had been in hospital for months before and while he was in hospital my grandma had dropped the keys to the garden gate outside and had never found them again, even though she looked every day for them. She never told my grandad because they always used to fight about where the keys were, and she didn't want to tell him she'd lost them. Then after he died, my grandma went outside, passing where she had dropped the keys and looked down- to see the two keys, perfectly stretched out with their keys on either side of their key-ring (i.e. not looking like they had just been dropped there) and with not a mark on them, even though they were lying in mud. She swears she checked that spot every day after she lost the keys and they weren't there.