Former baseball superstar Roberto Alomar is getting married Wednesday, along with thousands of others who believe the date 12-12-12 marks an auspicious, once-in-a-lifetime occasion -- not to mention a wedding anniversary that's easy to remember.

David's Bridal estimates more than 7,500 U.S. couples alone will get married on Wednesday, planning mid-week nuptials in order to capitalize on the date. In Canada, some 381 brides registered with the retailer say they'll be getting hitched on 12-12-12.

The Little White Chapel in Las Vegas has 300 weddings scheduled for the day and, in Hong Kong, 12 couples are getting married in a mass joint-ceremony.

While Alomar -- a former Toronto Blue Jay who wore the number 12 on his jersey -- has a personal attachment to the date, others believe the number 12 is symbolic of completion or represents good luck.

And it's relatively rare: it will be another 88 years before the next repetitive date appears, when every number is the same when viewed in the year/month/day format.

For some, it's simply a good opportunity to hold their wedding on a memorable milestone.

Krisztina Sebesi, 34, and Rex Lu, 26, are among those Canadians choosing to exchange vows today.

"We looked through the calendar and we were like, 'Oh, my god! 12-12-12,'" Sebesi told The Canadian Press. "It's an iconic date. It's the last of our lifetime for sure. And we're like, 'Let's do it. Let's do that day.'"

The Brampton, Ont., couple planned a destination wedding in Aruba, complete with a sunset ceremony and a reception that will feature a dozen courses, a cake with 12 starfish and thank-you cards decorated with 12 coconuts.

"It represents who we are -- and we are unique," Sebesi said.

While some had predicted 12-12-12 would mark the end of the world -- largely due to its proximity to the so-called Mayan doomsday later in the month -- the Astronomical Society of the Pacific has declared Dec. 12, 2012 to be "Anti-Doomsday Day."

In a statement, the group said the date should represent a "celebration of rational thinking and reasoned discourse."

"We also feel that, in many respects, the number 12 is most auspicious: contemporary calendars (12 months in the year), chronology (12 hours of day and night), traditional zodiac (12 astrological signs), Greek mythology (12 Olympic gods and goddesses), holiday folklore (12 days of Christmas), Shakespeare (Twelfth Night), and of course in our culinary world (dozen eggs, case of wine)!"

Even more importantly, the society notes that the planet Mars is located 12 light minutes from the sun, the average temperature on Earth is 12C and Jupiter takes 12 years to orbit the sun.

And because of the day's importance, it also marks an appropriate time to make a donation of $12, $24 or $36 to the ASA, the statement added.