You can see events via Events button on Main Menu.
On Events, there are certain requirements (play matches, score points, win games, gain supporters, use super powers etc.) for each step and the rewards get more valuable as you progress further.
You can also compete with other users on Event Leaderboards which start at the same time with events. You can obtain extra rewards by claiming high standings on Event Leaderboards.
All endings are also beginnings of new events.