The game works like this.
You have two teams of two, and you all must be in creative mode. Everyone pick a snowball, and throw off to see who gets to press the button. To throw off, you must stand on the snow blocks in the center of the stadium, and attempt to throw the snowball into the centerpiece. However, there appears to be a glitch where the snowball disappears instead. This does not count.
When the mob spawns, everyone needs to pick up a side. There is red, and green. Everyone must stand, and stay on the desired platform, and the team who won the throw-off must press the button to the right. When pressed, a mob will spawn in the middle of the field. There is a Cow, a Chicken, and a Squid.
Then throw snowballs at the mob to push it into the other team's territory! The cow is easy to work with, while the chicken and squid are a little harder. The chicken will move around much more, while the squid acts like a rock. Once the mob goes in all the way into the other team's territory, a light behind the team who won will light up. Remember to play on peaceful! Lest you want creepers blowing up the wool and redstone! Have fun!

Additional Notes

Please, give me suggestions for future ideas!
I might be able to make variations of the game every now and then,
here's what to look forward to!

Snowball Barrage! Ocean Edition

Snowball Barrage! Nether Edition

Snowball Barrage! Hardcore Edition