EA Mobile is rolling out a free-to-play version of everybody's favorite "dice in a cup" game - Yahtzee! But "this is not your grandmother's Yahtzee," as the game puts it - instead, World Series of Yahtzee challenges players to see who can roll the best score in 90 seconds. Players can go head-to-head against Facebook friends or square off against random strangers by way of the game's "Guest Mode."