Denise Gordon, an editor at Glamour magazine, was to give birth to twins today -- 6/6/06.
She had serious reservations.
"I don't want them to have this birthday. There could be a stigma attached to it," she said.
Gordon and many other expectant mothers rescheduled their planned Caesarean sections for Wednesday -- if there is a Wednesday.
So what's the fuss all about? In the Bible, Revelation 13:18 says: "Let him that hath understanding count the number of the beast: for it is the number of a man; and his number is six hundred, three-score [and] six."
In other words the number of the beast or Devil is 666.
In the 1976 horror film "The Omen," Damien had that number on his head. He turned out to be the anti-Christ.
Some people believe that bad things will happen on days associated with 6-6-6 -- even the ultimate bad thing: the apocalypse.
Robert Hodgson of the American Bible Society describes the apocalypse as a "period of tribulation."
"This will be a certain amount of time when there might be wars and pestulences and floods," he said.
It isn't just fanatics who are skittish about 6-6-6. President Reagan and his family changed the address of one of their houses from 666 to 668.
While some are scared of the number, others are cashing in.
A remake of "The Omen" opens in theaters today. The town of Hell, Mich., is throwing a party, and a gambling Web site is even giving odds -- 100,000-to-1 -- that the planet will survive the day.
If you win, how will you collect the bet if the world has ended?
ABC News' John Berman originally reported this story.