They are hoping the lure of a wedding license stamped with a once-in-a-century 12-12-12 will help boost revenue. Sin City's share of the weddings business has fallen by a third since 2004 as cities from New Orleans to New York have gotten into the elopement industry.
"From a marketing perspective, it's a very big deal. Numbers are associated with Vegas," said Ann Parsons, marketing director for Vegas Weddings, which runs four chapels in town. "Unfortunately, it's the last date like that we'll have."
Chapels from the rundown courthouse area to the ritzy Strip are jumping at the chance to sell 12-12-12 packages at three times the normal price for weekday ceremonies during the wedding offseason, from November to April.
In the absence of any obvious symbolism - like 7-7-07, which gamblers will recognize as the numbers for a lucky slot machine winner- chapels are turning to Chinese numerology.
"One is considered a yang number, while two is considered a yin number. Combining the two can offer new couples balance," the marketing firm Back Bar USA said in a press release announcing its $1,212,120 wedding package that includes the use of a private jet, watches and earrings for the wedding party, and dinner at a Michelin-rated restaurant.
Triple digit wedding dates have become a lifeline for struggling chapels, said Joni Moss, a longtime Las Vegas wedding planner and founder of the Nevada Wedding Association.
"Everything has declined," she said. "The small facilities here are really worried and figuring out how to market themselves."
Over the years, the city has become known for such nuptial innovations as drive-thru weddings, over the top themes, and Elvis look-alikes playing minister.
The boom in competition means real heartache for the city of lights, where weddings are the second largest industry after gambling, and newlyweds bring in about $800 million annually, according to the Las Vegas Convention and Visitors Authority.
Clark County, where Las Vegas is located, issued a third fewer wedding licenses for Nov. 11, 2011, which attracted a large share of veterans and fell on a Friday, than it did for July 7, 2007.
The county captured 5.7 percent of the U.S. wedding market in 2004 compared to 4.4 percent in 2010, the last year the stats are available. Overall, speedy weddings and destination ceremonies are more popular than ever, according to The Wedding Report, an online market research firm.
More people are getting married at ages when they no longer need a gift registry to fill their kitchens or a "Big Day" to mark the transition to adulthood, said Linda Waite, a sociology professor at the University of Chicago.
And with budgets tightening and wedding costs spiraling ever upward, the stigma is falling away from getting hitched on the cheap. As a result, businesses and cities across the country are looking to attract couples fleeing the wedding industrial complex.
New York Mayor Michael Bloomberg turned the Manhattan Marriage Bureau into a gleaming 24,000-square-foot wedding palace in 2009, saying he was setting out to give Vegas a run for its money.
"Not everybody particularly likes Vegas," said Carolyn Gerin, co-author of the Anti-Bride Guide. "There are all sorts of business that have sprung up to cater to brides that want to do it differently. It's like, why would they leave money on the table."
The lure of getting married in Las Vegas has long been tied to the state's streamlined wedding laws, which allow couples to skip blood tests and waiting periods. In recent years, other states have also hit the accelerator on their marriage license process.
Mississippi enacted a "quickie marriage" law this year to attract visitor and similar legislation is under consideration in New Jersey. New Orleans saw a jump in marriage tourism after eliminating its waiting period in 2003, according to the Louisiana Department of Tourism.
"I feel like everyone who is getting married considers Vegas. I've just never liked it that much; it's tacky," said Nina Baltierra, 27, who eloped in 2010 after spending months planning an increasingly elaborate 200-person wedding in rural Pennsylvania.
Instead of flying to the desert, Baltierra and her groom called in sick and drove to New York City, where they were married in Central Park by a photographer and officiant team who do a brisk business in public, "guerrilla-style" elopements.
"It only took an hour and a half to get to New York City and the possibilities there are endless," Baltierra said.
In Las Vegas, the industry is not giving up on the gimmickry that is its hallmark. Chapels are already starting to market "Armageddon Wedding" packages for Dec. 21, 2012, the close of the Mayan calendar said to portend the end of the world.
The quickie wedding in that case could make for very some short marriages.