I haven't seen a ghost, but I have a friend who heard one.

Her grandpa had died years ago, and her grandma was dying of cancer. One day she told my friend that she wasn't afraid of dying, because it meant she would be with her husband again. A week later she died.

The night after the funeral, my friend woke up and heard music playing on the floor above her. She went to look, but there was nobody there, and none of the CD players were turned on, but the music was still playing. She thinks her grandma and grandpa were finally dancing together again.

Ah goodness, I'm crying now. That's always such a beautiful story to me.