This is an account from my twin cousins, who are not prone to exaggeration, so I take them at their word on this:
About 15 years ago, my uncle (my dad's brother), my aunt and my two cousins (each 15 at the time) inherited a new grandfather clock when my aunt's father passed away. The clock is more than 150 years old and features intricate carving work on the body as well as paintings depicting 19th century rural life on the boarder surrounding the face.
The night before Thanksgiving, they put the clock in their foyer and wound it to get it running so that it would be on display when they hosted the whole family for the holiday. They proceeded to prep the house for the impending company, cleaning and setting out cups and dishware so they'd have less to do in the morning. That night, my aunt and uncle were woken up by conversation downstairs, followed by what sounded like marbles dropping on the kitchen floor. My uncle got up to tell my cousins to get back to bed, but as he passed their rooms, he noticed they were still sound asleep.
As he went downstairs to check it out, the talking stopped, but he noticed the cups they had set had been moved around as if they'd been used, and ice was scattered across the floor beneath the refrigerator's ice dispenser. Somehow, he shrugged it off (I would've moved out the next day), and didn't even mention it when we all visited on Thanksgiving.
Thanksgiving night, after everyone left, one of my cousins was in bed when she heard what sounded like a little boy laughing. The door to the hall was open and when she looked to see what the sound was, she said she saw the shadow of a little boy run down the hall, followed by the shadow of a man in what appeared to be a top hat. In the morning, when she told her sister what she had seen and heard, she found out her sister had seen and heard it too.
Needless to say, that next night they slept in the same bed. They huddled together and pulled the sheets up over their heads, and when as they were about to drift to sleep, one was woken up by the sound of footsteps in the hall and noticed it had woken her sister up as well. The footsteps continued until the girls noticed the footsteps sounded closer, like someone was pacing across the wooden floor in the room with them. My cousin who was on the outside position in the bed pulled her covers down to peek and see if she could find the source of the noise, when she said she saw a shadowy figure stop and turn to look at her. She screamed and turned on the lights, and it was gone.
When my aunt and uncle ran into the room, she told them what she had seen, her sister backing up that she'd heard the footsteps. My aunt and uncle believed them, having experienced some of the strange sounds themselves. To this day, they say what was hardest at the time was that they couldn't think of anything to say to offer their daughters any relief.
A couple days later, my uncle had to leave town for a business trip, so my aunt and two cousins slept together on an air mattress in the living room. They had put on a movie for some background noise to help them sleep. At 330a one of my cousins said she woke up because the room had turned ice cold, despite the heat being on. The sleep timer had turned the TV off, but she said when they looked toward the glass doors that led to the back deck, she saw the silhouette of a little boy and little girl just inside the door, standing there holding hands and watching them sleep.
Horrified, she nudged her sister and mom, who both saw the chidlren as well. My aunt jumped off the air mattress to hit the light and, and like that, they were gone. They said the room steadily rose back to its normal temperature, while the kitchen, just one room away, had stayed warm the whole time.
They weren't disturbed again for the two following nights before my uncle came back from his trip. When he got home, he noticed the grandfather clock had stopped, needing to be wound again. The time on the clock was 330.
The four of them connected the strange happenings to the clock, especially since the activity seemed to stop when the clock did. They never wound the clock again and they've not experienced anything since.
For whatever reason, they never got rid of the clock (I would have burned it). My aunt and uncle have since divorced, and she keeps it in the hall of her new apartment, but still, 15 years later they haven't experienced anything else, and they've never wound the clock since. To this day, they won't use the word "ghost" to describe the figures they saw. In fact, they don't like to talk about it at all. But when they do, you can see their faces turn white, their eyes get glassy and the hair on their neck stand up.
I won't behaving any grandfather clocks in my house.