The Hunger Games trilogy
The first book begins with Katniss making sacrifices to feed her family. She has to do this because District 12 is a very small, poor district.  One day , the Capitol Peacekeepers, the police of Panem, come to District 12 and set up the raffle system for the Hunger Games. The adolescents of District 12 line up. Each gender forms it own line. The Head Peacekeeper pulls 2 names from the raffle. Peeta Mellark, a boy from the richer center of town, is the first chosen. The Head Peacekeeper reads out Katniss's sister Primrose's name. Katniss objects and volunteers to be in the games in her sisters place.