The new worlds pick'em contest is live here!.
There's two levels of prizes this year:
"Unlock the unique 2017 Pick’em Poro icons by participating and by scoring at least 34 points. Get everything right and you will unlock all four Ultimate skins!"
On top of the regular prizes, there's also in game missions that let you get additional loot. If you log into League, you'll notice there's a mission that asks you to set your picks and a follow-up that gives you worlds points if you get at least 34 points.
Tl;dr is log in, set picks, get a bunch of free stuff :)
As a reminder the group stage for Worlds starts on Thursday, October 5th:
