Achievements
From PinataIsland.info, the Viva Piñata wiki
Xbox Live achievements will be detailed here
Achievements are awarded to Xbox 360 gamers for accomplishing certain feats in a game. They unlock a certain amount of gamerscore. Viva Pinata players will be able to unlock most to all of the achievements no matter how they play.
One of the initial achievements is unlocked by renaming a pinata.