If you're a follower of the Julian Calendar, it's the New Year and the new millennium. Happy happy.
You know, if you're Ethiopian it's a big day. And before you get all self-righteous or whatever, our Western Culture invented the Julian and then adjusted with the Gregorian losing 12 days. And it wasn't all that long ago. Where as most other places followed older lunar based calendars which didn't have as much error in them as the European Lunar Calendars did.