The Captain Scarlett and her Pirate's Booty Add-on for Borderlands 2 (Xbox 360) has 3 achievements worth 125 gamerscore.
Achievements they've won
Achievements they've not won
Complete all Pirate's Booty side missions
Discover all named locations in Oasis and the surrounding Pirate's Booty zones
Complete the mission "X Marks the Spot"