Puzzle Pirates

Yohoho! Puzzle Pirates is a Massively Multiplayer Online Role Playing Game. It is developed by Three Rings Design. In this game, the player plays a role of a pirate. The player sails the ocean, plays different puzzles and earn PoE (Pieces of Eights).
Anyone over 13 years of age can play "Puzzle Pirates". Pirates can join a crew, which in turn joins a flag. The flags forms alliances and blockade islands. 
The game encourages players to use pirate-themed words like "Ahoy", "Yarr!", "Shiver me Timbers", etc. As of December 2008, there are 4 million pirates registered to the game. On August 31, 2011, the game was made free-to-play on Steam.