I was walking around a beach town when I suddenly remembered the movie "Summer of '42." (A teenaged boy in a summer resort town has a crush on a woman whose husband is serving in the war...) Remembering the movie, I felt like I had to know: was the movie really based on a true story?

It turns out the answer is yes, according to Wikipedia. And there's two more big surprises...
  
After the movie was released in 1971, the author of the story actually heard from that woman he'd known on the island beach resort, 30 years before. "She was one of over a dozen women who wrote letters to [Herman] Raucher claiming to be 'his' Dorothy.

Raucher recognized the 'real' Dorothy's handwriting, and she confirmed her identity by making references to certain events only she could have known about. She told Raucher that she had lived for years with the guilt that she had potentially traumatized him and ruined his life. She told Raucher that she was glad he turned out all right, and that they had best not re-visit the past."

And the actress who played Dorothy actually wrote a short story in which Herman returns to the beach resort 20 years later -- and meets up with Dorothy again! (Or more accurately, she returns to the beach town, and impossibly, sees teenaged Hermie yet again, only to realize later that it's his son...)