Today is 12-12-12 - A calendar date -- and a concert -- of a lifetime

12-12-12 is here: It's an eye-popping quirk of the calendar that has brides running for the altar, some wondering whether the world is going to come to an end and setting the stage for what is arguably the single greatest concert lineup -- and the single largest concert -- the world has ever known.

Plus, it's just kinda cool. (You know what's even cooler? At two points today, it will actually be 12:12:12 on 12-12-12!)

Assuming the world does not end today, 12-12-12 will mark what some believe will be the greatest concert lineup of all time: The 121212 Concert will be held tonight in New York's Madison Square Garden to raise money for victims ofSuperstorm Sandy. It will feature Bruce Springsteen, the Rolling Stones, the Who and Paul McCartney, to name a few. 

It's estimated that more than 2 billion people around the globe will have access to the concert through a variety of broadcasts including movie screens, TV screens, computer screens and smartphone screens -- and, no doubt, a blizzard of social media updates using the designated #121212CONCERT

Such numerical happenings as 12-12-12 spook some people while enthralling others. Some see the tick, tick, ticking of the calendar as magical or especially lucky.

That might explain why Las Vegas -- and courthouses across the country -- are bracing themselves for a flood of brides and grooms who believe that getting married on 12-12-12 means never getting in trouble for forgetting your wedding anniversary.

The Clark County Clerk's Office, for example, is urging newlyweds to fill out their paperwork in advance to help save time on long lines, according to Fox 5 in Las Vegas.

Note to wannabe brides who want the iconic wedding date but don't have a groom: There's always 11-12-13!

Not everything associated with 12-12-12 is so upbeat.

There are some who believe that the Mayan calendar suggests that the world will come to an end on 12-12-12, while others believe that Doomsday is actually 12-21-12.

One thing is for sure: Unless someone, somewhere figures out a way to make us all live forever, we won't ever see a date on the calendar like 12-12-12 again.