Minecraft Hunger Games Servers are based on movie with the same title, the players would spawn in arena and would then have to fight with each other.
The main goal is to survive until there is one man standing, which can be hard since everyone starts with kits, which contain food, weapons, potions and other items.
Minecraft Hunger Games Servers maps and features
Most of Hunger Games Servers would usually have own maps and features based on Hunger Games plugin they're using.
Such servers would also implement rescue packs, chests with starting gear and in some cases even custom skills and upgradable items.