Events are features that are available for a limited time. They are optional.
So far there is only one type of event available in the game. It requires the players who participate to prepare a certain number of packages before the event ends. Completing packages is only possible through completing match-3 episodes. If you complete a match-3 level at first try, you get to prepare more packages. If you reach the goal in time, you get the big event reward. But there are also rewards available along the way.