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.]