Some people devote their lives to ending world hunger, some to lifting children from poverty, and still others to getting Leap Day the respect it deserves.
The cause may seem frivolous but it is not the least bit trivial to leapers, those born on February 29, a date that appears on calendars once every four or sometimes eight years.
Leapers face a range of troubles over their birthdays, from computer snafus to police suspicion during traffic stops to hearing about delivery room negotiations to alter their birth certificate to a day earlier or a day later.
"I've had people tell me to my face, 'Who cares?'" said Raenell Dawn, who with Peter Brouwer in 1997 created The Honor Society for Leap Year Day Babies. The online club for people born on February 29 boasts more than 9,000 members.
"I'll tell you who cares. One in 1,461 of us do," Dawn said, citing the chance to be born on Leap Day. There are just over 200,000 leapers in the United States and just under 5 million worldwide, she said.
Lest non-leapers dismiss leapers' complaints, leapers point out that salaried employees are working for free this February 29 since paychecks are based on a 365-day year.
February 29 is not recognized by some computer services and software programs that power everything from banking to life insurance, Brouwer said.
"Leap year deniers claim February 29 is an invalid date," said Brouwer, who said he was told by Crown Life Insurance Co. that March 1 had to be listed on his policy because the company's computer system balked at his February 29 birthday.
EIGHT LONG YEARS
Leap Day has tripped up Google, whose Blogger program will not allow existing users born on February 29 to update their profiles, an annoyance to leapers who use social media. A Google spokesman said the company plans to fix the glitch.
Leap years occur every four years, except those ending in double zeros, such as 1900 and 2100, said Geoff Chester, a spokesman for the United States Naval Observatory.
To confuse matters, there is an exception to that exception: Years ending in double zeros that can be evenly divided by 400, such as 1600 and 2000, are in fact leap years.
Microsoft's Excel, the world's most popular spreadsheet, doesn't realize that 1900 was not a leap year and as a result myriad other companies' programs, in order to be compatible, have had to put the error in their code. Microsoft has no plans to correct the mistake because "fixing it now would cause greater impact to customers," a company spokeswoman said.
Because there is no leap year in 2100, anyone born this February 29 who lives a long life will have no birthday from 2096 to 2104.
"Eight years is a long time not to have a birthday," Brouwer said in an email statement illustrated by a sad-faced emoticon.
These mathematical gymnastics have been executed since about 44 B.C., when Julius Caesar instituted the leap year system to correct a defect in the calendar that would otherwise put the seasons out of sync, said Chester, whose great-grandfather Rear Admiral Colby Chester was born on February 29, 1844.
SWEET 16 AT AGE 64
Because of their quadrennial birthdate, leapers have been known to invite people to their Sweet 16 party to mark their 64th year, Brouwer said.
"It's my 20th birthday but I'm going to be 80 years old," said Mary Ann Brown, born February 29, 1932. She is founder of the Worldwide Leap Year Festival, held every fourth year since 1988 in Anthony, a town straddling the border of New Mexico and Texas.
Dawn and Brouwer's activism to right Leap Day wrongs has included lobbying calendar companies to mark it as a notable day, like New Year's, and prodding Facebook to clear the block on February 29 as a birthdate on its user profile pages.
Facebook complied, but the calendar effort has so far been largely unsuccessful, they said.
"We're not curing cancer or stopping world wars but it still is a significant thing that needs to be addressed. It does affect the whole world," Dawn said.
For most people, February 29 is a quirky extra day to enjoy life but for at least one person it's Doomsday. Arizona death row inmate Robert Henry Moormann, 63, is scheduled to be executed on Leap Day for beating, stabbing and strangling his adoptive mother and dismembering her body during a "compassionate furlough" from prison to visit her in 1984.