Read The Hunger Games
The Hunger Games all started with 13 districts, and a rebellion. When districts 1-13 first rebelled, District 1 put an immediate stop to that by destroying District 13. So now every year, each district must send a boy and a girl to the capitol to be put in an arena to compete and kill each other until there is only one "tribute" left. The winning tribute's district gets food packages once a month until the next Hunger Games, which happens each year. The winning tribute lives in a big house,always has enough food, and never has to go to the Hunger Games again.