The Version You Know
Sleeping Beauty is the story of a young Princess who is cursed by an evil witch so that she will prick her finger on a spindle and die on her 15 birthday. The old woman does this because she wasn't invited to the party celebrating the girl's birth, where other good fairies/wise women are bestowing gifts upon her. Fortunately, one still hasn't given her a gift, and so tempers the curse--the Princess won't die, she'll just fall asleep for 100 years. We guess she did what she could, but still, a pretty major downer for the party.
Of course the King orders all spindles burned, plunging the kingdom into a fashion nightmare, but with the inevitability of fairy tale logic bearing down on her, the princess manages to find the one working spindle in the kingdom, and pricks her finger on her 15 birthday. She falls asleep for 100 years, until a dashing young Prince comes along in timely fashion and kisses her, breaking the spell. Everyone lives happily ever after.
What Got Changed
The first major departure in this from the version we know today is when the Princess pricks her finger on her 15 birthday. In earlier versions the Princess instead gets a piece of flax caught under her fingernail which pricks her and puts her to sleep. This might seem like a small difference but it becomes important when you consider the other major, and unsettling, change to the story.
Previous versions of the tale have the Prince who finds Sleeping Beauty think she's so damn beautiful he just goes ahead and has his way with her right then and there. Yes, while she's still comatose.
If that's not disturbing enough, the rohypnol-style coupling leads to a pregnancy, and the Princess gives birth to twins, all while asleep. One of the babies, seeking momma's milk, sucks on her finger and dislodges the flax, waking her, at which point we imagine she had a few questions.