You're likely familiar with some of the old content, such as the firepoles and stealing flames, but as the Schramm mentioned yesterday, there's a ton of new stuff, too: Ahune the Frost Lord, torch tossing, torch catching, a pocket firedancer, and some pretty fab Fire Festival clothing.
Get on out there and have some fun, and make sure to check back throughout the day. We'll have a lot of Fire Festival content of our own coming your way, right here on WoW Insider! Oh, and before you go questing today, stop by the firepole and dance with some friends. This year, it gives you a pretty nice boost to XP gains!