The Event gold was put in to safely sell gold to other people. You can redeem it from the Boutique NPC I believe and you buy items off the Event tab when you press O to open the cubi shop.
Event tokens are received through several mob events like Fire Legion (activated by GMs) and Ares (150 only boss quest that happens on Sat). Other than that, events that GMs host also give out Event Tokens and other prizes. These events can include fashion, pvp, trivea, hns etc