Today, February 29, is Leap Day. It occurs only every four years, in years evenly divisable by 4, such as 1988, 1996, 2008 or 2016 (with the exception of century years not divisible by 400, such as 1900). These are called Leap years. Leap days are more likely to fall on a Monday or a Wednesday.
Although the modern calendar counts a year as 365 days, a complete revolution around the sun takes approximately 365 days and 6 hours. Every four years, an extra twenty-four hours have accumulated, so one extra day is added to that calendar to keep the count coordinated with the sun's apparent position.
A person who was born on February 29 may be called a leapling or a leaper. In non-leap years they may celebrate their birthday on either February 28 or March 1 (some countries/states have different laws on this). There is also still the odd computer programme that is thrown in confusion if someone types in a date of February 29 as a date.
Leap day is perhaps best known for the tradition that allows women to propose to men on this day, supposedly based on an old Irish tale of a bargain made between St Bridget and St Patrick. In some places if the man turns the woman down, he has to pay a forfeit. It is unluck to be born on this day in Scotland or to get married today in Greece.
And when it comes to trivia – on this day in 1692, the first accusations were made in the Salem witch trials, on this day in 1952 the first “Walk/Don’t Walk” signs were erected in New York City and in 1933 former Governor General of New Zealand Sir David Beattie was born.