Well event works like this.

You'll get a newsletter and you'll see the announcement that the event is underway. The event forum will open up.

Once that happens, you'll be able to earn a second type of currency, Event Currency. How you earn it varies a little every event. We like to keep you guys on your toes.

That Event Currency is what you use to redeem for the EIs.

In the event forum you can hangout, chat, buy/earn/win art, play in staff event threads, talk to NPCs, and so much more.

Also event commons are released and only for the duration of the event are they offered at 50% so save up!