Not to everyone's taste, but there is a bum with a sandwich board that says "The End Is Near". He walks around from time to time, barely noticeable. But he's not who he appears to be and ultimately it's hard to know if he's seriously crazy or seriously sane.
Certainly most of the people in the story are insane, although technically they are quite "normal".
Read the GN a while back. We need a Dr. Manhattan.