Nothing out of the ordinary will happen. Maybe more people will consume psychedelic substances than usual.
Hey, at least that will account for something
You don't think people will do crazy things on the day we have all been waiting for our whole lives?
I imagine there is going to be a lot of out of the ordinary things happening, A little terrorism, some bankers getting charged, and a lot of the worlds insane killing themselves and there we have "the end of the world as we know it"... even if it is only slightly different :p