This is my mother's experience not my own, I love this site and hope that this story will make it into this site's collection.
My mother was a teenager and was babysitting for a family that had been living in the area for a couple of months. My mother was upstairs and had just finished putting the two year old girl she had been babysitting to sleep.
Suddenly a heavy breathing sound started to fill the room, it was a heavy deep breathing sound and it sounded like an adult male. Since there were only two people in the house my mother assumed that it was the television or somebody outside. She turned off the TV and closed the windows but the breathing continued. By this time she was considerably scared and then realized, disturbingly enough, that the sound was coming from the other side of the room.
That's when the someone or something seemingly walked up to my mother and breathed right in her ear. She panicked and picked up the two year old girl and waited for the family to come back, on the porch for the rest of the night.
Oddly enough the young girl stayed asleep the whole time as if the thing breathing was only targeting my mother and couldn't be heard by anybody else. My mother also says that the woman who lived in the house was constantly asking if anything, particularly something out of the ordinary happened while she was away to which my mother always responded no.