Pet Society: Throw a shindig with the new Party Invitation and Surprise Birthday Box

Pet Society, Playfish's popular pet simulation game on Facebook, turns two this week (on August 8 to be exact). Basically, Pet Society launched before Facebook gaming became a 'thing,' so it's refreshing to see that one of our favorite social games seems to have some longevity. But, I digress.

In honor of the big birthday, Pet Society's weekly update includes a slew of party-themed items, which includes two new collaborative items: the Party Invitation and the Surprise Birthday Box.