Recently Clash of Clans sent an email to its players about the start of the Clash Fest Tournament. After clicking the email, you will be redirected to the Clash of Clans events website. You can log in with your Supercell email and password which will take you to the predictions page. Here is the list of the rewards you will get after making accurate predictions:
Even if you missed predicting the older matches, you can still make predictions and earn free gem rewards. Just watch the previous streams and get the free influx of gems.
That's a total of 1225 free gems! You can get free rewards for Clash Royale too. The Clash Fest event is the biggest event for Supercell games. The rewards are huge and easy to earn. I don't think anyone should miss those free rewards. You can go to the Supercell Events website by clicking here.