Warnings by a US fundamentalist preacher that Saturday is Judgment Day have sent some people into hiding or scrambling to repent, while others are planning parties to wave off good Christians.
89 year old teleevangelist Harold Camping's prophecy says the Rapture will begin with powerful earthquakes at 6:00 pm local time in each of the world's regions, after which the good will be beamed up to heaven.
The not so good will suffer through hell on earth until October 21, when God will pull the plug on the planet once and for all, he predicts.
In the United States, where Camping's evangelizing organization is based, some people have been quitting their jobs and hitting the road to urge others to repent before it's too late.
Gregory LeCorps left his job "in a medical facility" weeks ago to take his wife and five young children on the road and warn others that the Rapture is really nigh, the Journal News in New York wrote. "We're in the final days," LeCorps, who said he hopes to be on a beach in South Carolina by Saturday, was quoted by the lower Hudson valley newspaper as saying as he handed out leaflets.
In Vietnam, thousands of ethnic Hmong converged on northwestern Dien Bien province a few weeks ago after hearing broadcasts on Camping's global religious broadcasting network, Family Radio, that Jesus was coming on May 21.
Hundreds are believed hiding in forests after security forces dispersed those who were awaiting the supposed return of Jesus Christ on Saturday, a resident told AFP.
The Vietnamese government said extremists used the gathering to advocate for a Hmong kingdom, but the resident said he was unaware of such talk.
In Ciudad Juarez, one of the hardest hit cities in Mexico's drug wars, huge billboards proclaim that "Christ is coming back on May 21."
According to the authorities, the apocalyptic message hasn't provoked panic or hoarding, but one resident, Rosy Alderete, said she was "worried by the coincidence" that big earthquakes have rocked Japan and New Zealand this year.
The London based Guardian newspaper described the looming Rapture as "the fundamentalist Christian equivalent of the last helicopter out of Saigon," referring to the US pullout after the long Vietnam war in 1975.
The fact that Camping wrongly predicted the end of the world once before, in 1994, has left others willing to make fun of him.
New York City Mayor Michael Bloomberg -- who is Jewish and therefore, according to Camping's prophecy, unlikely to be beamed up to sit alongside Jesus and God in heaven -- said on his weekly radio show on Friday that he would suspend alternate side parking in New York if the world ends on Saturday.
The much reviled parking rule requires New Yorkers to move their cars from one side of the street to the other to allow street cleaning to be carried out.
And some are cashing in on money making opportunities.
Craigslist was running tens of thousands of ads from non-believers offering to buy the worldly goods of those who think they're going to heaven, while a group of US atheists has sold hundreds of contracts to rescue people's pets.
A group of Christians, who think Camping's prophecy is bunk, will be tracking the Rapture and posting reports on the Internet each time it doesn't happen. One of the first places to be hit, according to Camping, would be New Zealand, where 6:00 pm happens at 0600 GMT, but the prophecy received little local media attention.
Mark Vrankovich, director of the Christian organisation Cultwatch, said he was not aware of any New Zealanders preparing for the end of the world. "Do not sell your house and give the money away, do not stop paying bills, do not say anything you will regret to friends and family, don't quit your job, don't leave your loved ones," the Cultwatch website advises.
If Camping's prediction does not pan out, one idea is gathering steam on Twitter to create an ersatz Rapture. A tweet suggests laying out old clothing and shoes on pavements and lawns on Saturday to give the impression that someone has indeed been beamed up.