You only have to be as smart as a fifth-grader to know that leap year comes with an extra day tacked on the end of February. But that one stray day every four years is as quirky for the things it is as for the things it isn't.

It is arguably the most unusual day of the year, and yet banks are open and postal workers are posting, which means it is no holiday. Searching "leap day" on Wikipedia returns nothing, though it is mentioned within the "leap year" entry. Merriam-Webster's online dictionary doesn't even have a listing for the day, and perhaps the most shocking thing of all: a conspicuous absence of greeting cards.

A search of the whole of Utah law finds not a single reference to the word "leap," leaving nit-picky questions about the legalities of things that did happen or should happen on a particular day when that day doesn't come around every year.

Thom Roberts, a lawyer with the Utah Attorney General's Office, said he is not aware of any leap-day legal gotchas. "I've called around to a couple of people I thought might have dealt with the issue and none of them have," he said.

Common law dictates a person advances in age the day before their birthday, "though most states have shifted over to the birthday rule, which dictates a person advances in age on the birthday itself," Roberts said.

Jill Laws, deputy director of the Utah Driver License Division, said the question of whether a person with a leap-day birthday would legally be old enough for a driver's license on the last day of February in a non-leap-year year has never come to her attention. Perhaps that's because Utahns born on leap day, and eligible for their first driver's license at age 16, will always have that 16th birthday during a leap year when there is a February 29th on the calendar.

Because leap day is infamous as a birthday it's likely to be a lively topic in hospitals' labor and delivery areas Friday. Kathleen Murphy, director of St. Mark's Hospital's marketing and communication, said babies born there on Friday will go home with frog-themed bath towels and a bib with a frog on it as a remembrance of their leap day birth. Aside from being a leaping critter, the frog is this year's leap day mascot in an awareness campaign about disease and other environmental perils threatening amphibians.

Colleen Proctor, nurse manager for labor and delivery at Intermountain Medical Center in Murray, said the hospital schedules as many as 12 induced and Caesarean-section births on a typical weekday. The nine deliveries on the hospital's calendar this Friday may show there's no aversion to raising a child who only has a birthday once every four years. "For us, it's going to be a day as usual, a normal operating day. I'm sure people will be talking about it all day," she said.

On the other hand, any hesitancy to scheduling a leap day delivery may create an opening for an otherwise booked hospital schedule. Expectant mother Vanessa Butcher said she is scheduled for a Caesarean section birth at St. Mark's Hospital Friday "because it was the soonest day available" but didn't realize until talking later with her mother that her baby boy will be born on leap day.

Leap day in 2004 fell on a Sunday, which is the day of the week the fewest babies are born, according to the Utah Department of Health's Office of Vital Records and Statistics. Yet the number of babies born that leap-day Sunday, 104, topped the 84, 95 and 92 babies on the other Sundays that February. The Health Department's statistics do not indicate what portion of those deliveries were scheduled.

So in addition to whatever leap day may or may not be, it is definitely a novelty that leaves plenty of time to contemplate how to treat it next time around.