It's been a looooooooong time coming, but - according to a report on Game Informer - next year you'll be able to get your hands on at least some of Final Fantasy XV, with Square Enix to release a playable demo of the title sometime next year.
Game Informer says this demo will show you some of the early part of the game, albeit with "some elements of the progression...altered in order to make it more suitable for a demo experience."
They're also saying that people buying Final Fantasy Type-0 HD, which is out on March 17 in North America, will get a voucher to download the Final Fantasy XV demo.
In case the Game Informer story gets pulled, you can see it screencapped below.
UPDATE - Game Informer has pulled the story.
Final Fantasy XV Demo Coming In 2015 [Game Informer]