I recently read The Hunger Games trilogy
The story is about a post-apocalyptic world (i.e. North America) where there are no countries anymore. There are only 12 Districts and the Capitol. There used to be a 13th District but it was completely destroyed during the last rebellion of the Districts against the Capitol.
Now the Capitol rules with an iron fist and to prove their supremacy, each year the districts have to “provide” two children between the ages 12 and 16 – one girl and one boy. Then these 24 are sent to a fighting area which only one winner will leave alive.
The protagonist of the books is Katniss Aberdeen and she fights in the 74th Hunger Games for her very survival.