I always imagined it as being the sky turning different shades of purple and finally seeing colors I've never seen before. loud lightening, thunder in all directions... I would hear god speak, then the sky would turn red, and I'd see angels coming down from the sky and devils go up and fight in the sky... kinda like in Raiders of the Lost Arc. It would last 40 years, then the earth would split and open all demons would be cast below, and then 2 weeks of rain will cleanse the earth and the paradise would grow from the ash and neutrient rich rain.
...or am I just crazy? :) What do you guys think?