By Martha Brockenbrough
Special to MSN Movies

Three of the biggest movies to hit theaters in the past decade have something surprising in common: They all came from books written originally for children or teens.

To appreciate how strange that really is, consider the possibility of a children's singer--Raffi, anyone?--taking over the adult charts. Or a children's TV show being something grown men would be excited to see at the midnight theatrical showing, the inexplicable enchantment of "My Little Pony" aside.

"Harry Potter," "Twilight" or "Hunger Games"? Which book/movie series is #1 for you? Tell us on our Facebook page.

Beyond the fact that "Harry Potter," "Twilight," and "The Hunger Games" series are kids' stories that became pop culture juggernauts, how alike are they, really?

Not very. Except in some surprising and amusing ways...

Bing: More about 'Harry Potter' | More about 'Twilight' | More about 'The Hunger Games'

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(Warner Bros./Summit Entertainment/Lionsgate)