2 1/2 hours, 6pm est standard time! Mr. Camping is an engineer after all he did his math precisely! well when he redid it after his error in 1994.
I find it tickles my sense of wonder when I observe this kind of human behavior, I don't understand it but it amuses me.
If just a few percentage points of his followers would burn their bibles, enroll in a math or geology class on Monday it would be a good thing. However, i don't see it happening with even a fraction of 1 percent. They will just look for another easy solution to their belief that humanity is worthless without a master.