1) Leap years occur quadrennially, that's everyfouryears. They're required because a solar year is almost exactly 365¼ days long, and over a four year period those four quarter-days add up to make one whole extra day. 2) Today is the 514th leap day to be observed since the first in 45BC. 3) The first thirteen leap years were 45BC, 42BC, 39BC, 36BC, 33BC, 30BC, 27BC, 24BC, 21BC, 18BC, 15BC, 12BC and 9BC. At this point Roman priests spotted they'd been adding leap years every three years, rather than every four as Caesar decreed, so all leap years were temporarily suspended. They restarted in 8AD, after which they continued every four years as intended. 4) There are only 24 leap years this century because 2100 won't be a leap year (ditto 2200, 2300, but not 2400). 5) Algorithmically, a year is a leap year if ((year modulo 4 is 0) and (year modulo 100 is not 0)) or (year modulo 400 is 0). 6) Leap year babies celebrate their birthday only once every four years. Raenell's one, and her website celebrates the joy of being special. 7) You have a 1 in 1461 chance of being born on February 29th. The odds are a lot higher if your parents have sex on May 29th the previous year. 8) Over a 400 year period, the odds of being born on February 29th lengthen to 1 in 1506. 9) About 44000 people in the UK, 220000 people in the USA and 5 million people worldwide are leap day babies. 10) The Queen sent no centenarian birthday telegrams on February 29th 2000, because there was no February 29th 1900. 11) Pope Paul III was born on February 29th 1468, the composer Rossini on February 29th 1792, actor Joss Ackland on February 29th 1928 and rapper Ja Rule on February 29th 1976. Traditionally, Superman's birthday is also February 29th. More leap day birthdays can be found here. 12) In a leap year you probably get paid the same for doing one day's extra work. Schoolchildren, on the other hand, get one day's extra holiday. 13) The Gilbert & Sullivan operetta The Pirates of Penzance revolves around a February 29th birthday. Frederic is a pirate's apprentice, free to return to respectable society on his 21st birthday, except that at the age of 21 he realises he still has 63 years to go. A leap child's lot is not a happy one. 14) Today is the first February since 1988 to have five Mondays (and the next will be 2044). 15) If you have a leap year birthday, you have to decide whether to celebrate it on February 28th or March 1st in non-leap years. In legal situations, for example learning to drive, UK law dictates March 1st. By contrast, New Zealand presumes February 28th. 16) Ladies, today is traditionally the day to propose marriage to your man. Hurry up, if you wait another 4 years just think how old he'll be. Why not send a postcard? 17) In any 400 year period, there are 97 leap years, after which the calendar repeats. The most likely days of the week for February 29th to fall are Monday and Wednesday. The least likely are Sunday, Tuesday and Thursday. 18) When Julius Caesar introduced leap years the extra day wasn't February 29th, it was February 24th. The Romans repeated the sixth day before March 1st, or "dies bissextus", and leap years are still sometimes called bissextile years. 19) Living through a leap day means one day longer to wait for your birthday and one day longer to wait for Christmas. 20)Sir James Wilson, former Premier of Tasmania, was born on February 29th 1812 and (unbelievably) died on February 29th 1880 - his 17th birthday. 21) Leap Day number 1s of the past six decades would make a fascinating compilation CD: Anthony Newley (Why, 1960), Cilla Black (Anyone Who Had A Heart, 1964), Esther & Abi Ofarim (Cinderella Rockefella, 1968), Chicory Tip (Son Of My Father, 1972), Four Seasons (December '63 (Oh What A Night), 1976), Blondie (Atomic, 1980), Nena (99 Red Balloons, 1984), Kylie Minogue (I Should Be So Lucky, 1988), Shakespear's Sister (Stay, 1992), Oasis (Don't Look Back In Anger, 1996), All Saints (Pure Shores, 2000), Peter Andre (Mysterious Girl, 2004), Duffy (Mercy, 2008), Gotye (Somebody That I Used To Know, 2012) and Lukas Graham (7 Years, 2016). [If you have Spotify, there's a 54 minute playlist here!] 22) Leap day is also St Oswald's Day, named after a 10th century archbishop of York who died during a feet-washing ceremony on February 29th 992. His feast is celebrated on February 28th during non leap years. 23) The Academy Awards have twice been awarded on February 29th - in 1940(best picture: Gone With The Wind) and 2004(best picture: Lord of the Rings III). 24) Are you tempted by a Leap Day birthday poem, some Leap Day clothing or perhaps a Leap Day tattoo? 25) Leap year rules make the Gregorian calendar accurate to 1 day every 3236 years. But far better is the modern Iranian calendar (eight leap days inserted into a 33-year cycle) which is accurate to 1 day every 110,000 years. 26) In the Chinese calendar, a leap month is inserted if there are 13 moons from the start of the 11th month in one year to the start of the 11th month in the next year. 27) Leap year babies endured seven consecutive years with no birthdays from 1897 to 1903, and will again from 2097 to 2103. 28) There has, just once, been a February30th. It happened in Sweden, and it happened in 1712. The Swedes needed to lose 11 days to come in line with the Gregorian calendar, but forgot to miss out February 29th in 1704 and 1708 so had to add an extra leap day in 1712 to get back in sync. Pity the Swedish babies born on February 30th 1712, because they never saw another birthday. 29) Brothers and sister Heidi, Olav and Leif-Martin Henriksen of Stavanger, Norway were all born on February 29th - in 1960, 1964 and 1968 respectively.