The current event, the Midsummer Fire Festival, is a great way to make some easy gold. I just ran through a few of the daily quests and visited about 10 of the fires spread around Azeroth and Outland and in short time I had made close to 30g.
There’s a pretty concise set of quest guides for the Midsummer Fire Festival over at WoW Insider right now if you need help. The event ends on the 5th of July so you have plenty of time to run around WoW and clean house on these easy gold quests.