"The Playground" by Ray Bradbury

Think back to some of your fondest memories of childhood.  Most of them involve playing with your friends.  Remember the carefree days at the playground?  But, what if the playground was a place of terror?  What if the other kids mistreated you?  Then you grow up and have a son.  Your wife dies.  And circumstances lead to your son being sent to the same playground you grew up at.  It is scary enough...but then you see a familiar child at the playground...and he calls you by your childhood nickname...
The playground is a masterpiece by the great Ray Bradbury.  Bradbury takes something that is innocent and a symbol of a happy time and crafts a story full of mystery and terror.  
He does not need to show gory details.  Bradbury uses implied suspense to terrorize the reader.  Track down this short story.  It is well worth reading.  My only warning is that you will never look at a playground the same way again.
This story belongs in...the Peril of the Short Story.