"Once upon a time..." always catches the attention of our five-year-old kid who has also learned the art of storytelling by starting with those magic lines.
As far as my two grown children were concerned they grew up with stories that started with "ONce upon a time..." for I told them stories every single night when they were kids in order to put them to sleep. Somehow, I have made it a habit to start my stories with that line even with my grandkid.
Well, what happened once upon a time when my kids where young enough to believe those fairy tales? Did I not run out of stories? Honestly, I did after I had narrated ALL the popular fairy tales I had to fabricate all the rest and sometimes fell asleep before they did. But that was a long time ago when kids believed and listened to stories that started with "ONce upon a time..."