As for myself, I've had a couple.
Some background information:
My grandmother passed away in September of 1998 from cancer when I was 13 years old. Prior to her death, my mother and I had moved in with my grandmother in order to take care of her during her last months. After which my grandmother had passed away, we chose to stay in the house atleast until I could finish high school. I never really got to say goodbye to her since the family agreed that they did not want me present at her passing. That night that she had passed, I had been spending the night at a friends house. She passed away in her bedroom.
The situation:
1) When she passed away, I knew it. I was laying in my friends bed and looked at the clock which read 11:31PM and all of the sudden I got a really heavy feeling, like I was completely alone, and the air was very thick. I knew right that minute that my grandmother had passed away. The next day I returned home. I walked in the kitchen to find my mother standing behind the counter. She says to me "Nanny passed away last night". ("Nanny" is what I called my grandmother). Without even thinking, I replied "I know". It wasn't until later that after noon when I asked at about what time my grandmother passed on. My mother told me she had died at 11:30, one minute before I had that intense feeling the night before. I was suprised, but at the same time I wasn't.
2) When I was 15, just over two years after my grandmothers death, some thing's started happening around the house. First, I was sitting at the dinner table alone eating some soup when I noticed the lamp which hung above the table started to sway. Officially creeped out, I reached up and held the lamp still. A few minutes later, it started to sway again, this time MUCH stronger. I called my mom into the dining room and showed her the lamp. She was held the lamp still and then let go and watched it sway again. I put my bowl in the sink and we decided to try and ignore it.
3) A few months after that, something else happened. Those two day's are some I will never forget. It was a Friday night at around 1:00AM and I was sitting at the computer in the study talking in an AOL chatroom. All of the sudden, I see a reflection in the monitor which caught me totally off-guard. It was like a shadow of a person walking quickly behind me. I turned around, no one there. It happened again. And yet again I looked behind me finding on the the wall. A few minutes went by. I had resumed my online conversations and forgot about the incidents. Then I saw another reflection in the monitor and then a heavy hand on my right shoulder. It was VERY noticable. I automattically assumed it was my mother. I asked her what she had been doing up so late. Needless to say, I didn't get a response. I turned around and saw no one there, then I realized that the apparent hand on my shoulder had gone. I WAS FREAKED OUT. I went around the house and turned all the lights on and then went into my mom's bedroom to wake her up. I told her what happened. Then she told me that she was just having a dream about my grandmother (her mom). That was the first time since I was a child that we slept in the same bed lol.
Something unique happened the next night, but I prefer to keep that private. It was quite an experience and I wish to keep that somewhat a secret. Only my mom and I know about it. Most people wouldn't believe me anyway. Lets just say that it involved an aparition in great detal.
3) On Thankgiving of 2000, it was the first time the whole family had been together since my grandmothers death. We were celebrating at our/my grandmothers house with a nice Thanksgiving lunch. Everybody took thier seats at the table. We left one seat open for my grandmother in honor of her. We all began eating and having a decent time. I looked over at my mom and told her that wished "Nanny" was there. Not even a second after I said that, the power in the house went out for about 3 seconds. We took it as a sign that that was her way of saying that she was there. Later that day my mom asked our close neighbors if the power had blinked at thier home earlier. Our neighbors said that the power did NOT blink. And our whole street was on the same power grid, so if infact the power did go out in our house, the whole street would have lost power as well.
One last one:
I almost forgot... my whole life, my grandmother had always told me that if I didn't smoke, drink or do drugs, then she would buy me a new car on my 18th Birthday. When I was 14, I smoked my first cigarette on the way home from school one day. The following weekend, my mom drove me about an hour away to Galveston to visit my dad for the weekend. I few hours later we recieved a phone call. My mom had been in a serious car wreck which totalled the car but left her with only a few bruises. An 18-wheeler had ran a red light and hit her from the side. The EMS medics and the police said that if the truck would have been going only a few MPH faster, then my mom would not be here today. Keep in mind, my grandmother passed away from cancer, from smoking.