Apocalypse World is the game that changed how I play rpgs. The theme of scarcity is woven into every rule and the MC rules tell you how the game works: how to keep pressure on the players to male the characther's lives interesting.
The second edition adds better rules for intertwining charachter histories, for chases, battles, and sneak-attacks. It also adds great playbooks that evoke Immortan Joe and the Doof Warrior, in addition to the inscrutable child of the maelstrom.
Buy it, play it, let it get real weird. Your friends will surprise you.
[5 of 5 Stars!]