This year, 7/7/07 provides a unique opportunity for superstition and marketing to come together: starry-eyed couples are tying the knot, casinos are over-booked and Live Earth concerts as well as the proclamation of the world's seven new wonders take place that day.
"Number 7 has a magic sacred side and the reputation of bringing luck," said numerologist Jean-Daniel Fermier. So several sevens could bring an extra dose of good fortune.
"Number 7 is the union of 4, symbol of matter, and of 3, symbol of the spirit," said Fermier, author of a French guide to numerology.
"A priori, July 7, 2007 is a good date for a wedding. The marriage may stand a better chance of success, though of course the date is no guarantee."
Among the crowds of lovers in line to wed that day is celebrity couple Eva Longoria ("Desperate Housewives") and French basketball hero Tony Parker of the San Antonio Spurs -- said to be superstitious.
Parker said in Paris this week that it was Longoria who chose the setting for their July 7 marriage -- the grandiose chateau of Vaux-le-Vicomte outside Paris. "Personally I don't care (where we get married). I've been talking about it every day for the last seven months. It's a girl's day," he said.
But back in March already, a member of a US wedding planning site told AFP that more than 30,000 weddings were planned for July 7, when in ordinary years only 12,000 couples would choose a Saturday in July for their marriage.
"This is the biggest day I've seen in recent years," said Kathleen Murray, deputy editor of theknot.com.
But David's Bridal, the largest US retailer of wedding gowns, says it alone will deliver a record 20,000 gowns for brides for July 7 weddings.
That figure is double the peak figure in a normal year, and the company estimates some 65,000 - 70,000 weddings across the country on July 7.
Even those impulsive types seeking to elope in the US wedding capital Las Vegas are likely to be disappointed, with the city's wedding chapels all booked up, according to the media. One, the Chapel of Flowers, has 113 weddings planned for Saturday, around three time the normal figure.
In Paris this week, one of the city's major department stores, Galeries Lafayette, said it had received 774 wedding lists for 7/7/07, against an average 290 for each of the 13 Saturdays from July to September.
"Reservations for this particular date were made long in advance," said Sonya Willigsecker of Ceremonia, a small French wedding planning company. "We have had to turn down at least 40 couples for this date," she added.
Would-be couples who organised too late can always try their luck in a casino or buying a lottery ticket instead, however.
In casinos, where 777 wins the jackpot on one-armed bandits, managers are offering special July 7 deals such as an overnight luxury stay with spa and dinner for 777 dollars, or the night of your life for 7,777 dollars.
In France, the state-owned lottery is offering a seven-million-euro super-prize on 7/7/07. "We expect four to five million people to buy tickets in comparison with three million for an ordinary draw," a spokeswoman at the Francaise des Jeux told AFP.
But interestingly Friday 13 this July will do better. The French lottery will offer a 15-million-euro prize.
July 7 is also the date chosen to announce the results of a contest to choose the seven new wonders of the world.
Swiss-Canadian filmmaker Bernard Weber, a former assistant to Italian filmmaking legend Federico Fellini, has launched a website where Internet users can vote and choose the world's "new seven wonders."
Among sites short-listed are the Eiffel Tower, the Acropolis in Athens and the Great Wall of China. Greek historian Herodotus chose the original seven, which included the hanging gardens of Babylon, the statue of Zeus at Olympia, the Colossus of Rhodes and the lighthouse of Alexandria.
And for those more interested in preserving the future than the past, the global Live Earth concerts funding Al Gore's foundation against global warming also take place July 7.
More than seven cities are involved however -- among them notably Tokyo, Shanghai, Sydney, Johannesburg, Rio de Janeiro, London, New York, Hamburg and Istanbul.
But one academic brushed off the 7/7/07 frenzy as pure nonsense.
"7/7/07 is not pertinent," said Jean-Pierre Brach, a professor of esoteric studies at Paris' eminent Institute of Higher Studies (Ecole Pratique des Hautes Etudes).
"A number must be interpreted within a given historical context," he said.
The media fuss over July 7, he added, was no more than "divinatory numerology invented in the 19th century and popularised worldwide by the Americans."