Bart Centre, an atheist from New Hampshire, started Eternal Earth-bound Pets in 2009. He offers Rapture believers an insurance plan for those furry family members that won't join them in heaven: 10-year pet care contracts, with Centre and his network of fellow non-believers taking responsibility for the animals after the Rapture. The fee — payable in advance, of course — was originally $110, but has gone to $135 since Camping's prediction.

Centre says he has 258 clients under contract, and that business has picked up considerably this year. But he's not worried about a sales slump if May 21 happens to disappoint believers.

"They never lose their faith. They're never disappointed," he said. "It reinforces their faith, strangely enough."