Zombies. Nuclear War. Global Warming. Ascension of your less-preferred political party. Intergalactic war. Incoming asteroids. GMO-induced food crisis. Supervolcano. Robot uprising. Wrath of God. Gozer the Gozerian.
I don't pretend to know what will bring on the Apocalypse (OK, sometimes I do, but not usually). In fact, I'm a long way from sure that it's really coming. However, you kind of have to admit that there's a distinctly apocalypsy smell to the air of late. So, yeah, I'm getting ready, and, call me crazy, but I think that you should, too.