I love me some farmville :P
And from wikipedia:
FarmVille is a real-time farm simulation game developed by Zynga, available as an application on the social networking website Facebook. The game allows members of Facebook to manage a virtual farm by planting, growing and harvesting virtual crops, trees, and raising livestock. Since its launch in June 2009, FarmVille has become the most popular game application on Facebook, with over 82.7 million active users and over 22.5 million fans in February 2010. The total FarmVille users are over 20% of the users of Facebook and over 1% of the population of the world.