1. October 22, 1844
Who: Samuel S. Snow, a preacher in the Millerite movement, led by the Baptist preacher William Miller
How he came by this date: A prophesy in the Book of Daniel states "Unto two thousand and three hundred days; then shall the sanctuary be cleansed" (Dan. 8:14). If you convert the days into years, and if you start in the year 457 BC – the year that Artaxerxes I of Persia decreed that that the city government of Jerusalem shall be re-established – then this takes you to 1844. Using the Karaite Jewish calendar, Snow pinned the date down to October 22.
What actually happened: Thousands of people gave away all their posessions, only to be surprised when the world did not come to end, and the day came to be known as "The Great Disappointment." The Millerites splintered into several religious groups, the largest and most mainstream being the Seventh Day Adventists, and the smallest and most unconventional probably being the Branch Davidians. Millerism has also influenced the Bahá'í Faith.
How she came by that date: As you will see in the next paragraph, the answer is "the hard way."
What actually happened: Charles Mackay's 1841 book, "Extraordinary Popular Delusions and the Madness of Crowds," describes it thus:
"Great numbers visited the spot, and examined these wondrous eggs, convinced that the day of judgment was near at hand. Like sailors in a storm, expecting every instant to go to the bottom, the believers suddenly became religious, prayed violently, and flattered themselves that they repented them of their evil courses. But a plain tale soon put them down, and quenched their religion entirely. Some gentlemen, hearing of the matter, went one fine morning, and caught the poor hen in the act of laying one of her miraculous eggs. They soon ascertained beyond doubt that the egg had been inscribed with some corrosive ink, and cruelly forced up again into the bird’s body. At this explanation, those who had prayed, now laughed, and the world wagged as merrily as of yore."
3.December 21, 1954
How she came by this date: Through automatic writing, Martin came in contact with beings from the planet Clarion, who told her that the world would be destroyed by flood and that the faithful would be rescued at midnight by flying saucers (or so she said).
What actually happened: Martin's followers, many of whom quit their jobs and gave away their possessions, gathered in her home to await the aliens. (Martin's husband, a nonbeliever, slept upstairs through the whole thing.) To avoid being burned by the flying saucer, her followers removed all metal from their persons, including zippers and bra straps. Midnight came and went and the group became increasingly agitated. Finally, at 4:45am, Martin said that she received another message from Clarions informing her that God was so impressed by her groups actions that He changed His mind and decided to spare the earth.
Who: Hal Lindsey, who has been continually predicting the end of the world since his 1970 book "The Late, Great Planet Earth," and who, in his 1996 book "Planet Earth 2000 A.D.: Will Mankind Survive?" wrote that Christians should not make any plans after the year 2000.
How he came by this date: Probably the same method he used to calculate the date of the end of the world in his book "The 1980s: Countdown to Armageddon," which is now out of print.
What actually happened: Despite his less-than-stellar track record, Lindsey is still at it. In 2008, he wrote a column for the conservative news site WorldNetDaily suggesting that Barack Obama is setting the stage for the arrival of the Antichrist.
[Editor's note: An earlier version mischaracterized Lindsey's views on Obama.]
5.October or November 1982
How he came by that date: Robertson has said that God told him about pending disasters on numerous occasions (including a West Coast tsunami in 2006, and a terrorist attack in 2007 – neither occurred). "I have a relatively good track record,” he has said. “Sometimes I miss.”
What actually happened: The world didn't end in 1982, but "WKRP in Cincinnati," did.