This happened to me in the early 80s in Dublin Ireland where I am from. I used to often stay in a friends apartment about a mile from the city centre. The apartment was in an old building converted into apartments and he lived on the top floor. His bedroom was fairly big and had two beds he slept beside the window and when I stayed I slept in the bed beside the wall.
One summers night when I was staying there we had gone to bed around 3am and after chatting for a while we both drifted off to sleep, I woke up around 6am feeling restless as it was a hot summer and I was stuck to the bed with the humid heat so I sat on the bed and lit a cigarette. The window across the room was wide open and it was already bright outside, after a few minutes I heard the sound of lots of children laughing and singing. At first it seemed a bit distant then it grew louder around this point my friend woke up and I asked him if he could hear what I was hearing and he said he had often been woken by the same sounds and was used to it but he never told anyone. HE was looking out the window at this point so I went over and looked out as well and we were both listening to all this laughter and singing after about what seemed forever it all just faded away, so I asked him what he thought it was and he reckoned that he thought the school just behind his apartment building must be haunted as it was during the summer all the schools would be on holiday but there would be nobody there at that hour of the morning.
Anyway even though the school was an old building and was still used as a school I guess whatever ghostly happenings were taking place must of been something from a past event at the school. Even though it's a long time back since it happened I can still remember it as clear now as if it just happened.
Anyone with a similar experience...