Ahhh... Leap Day... Wikipedia has taught me much. For example:
February 29 is a date that occurs only every four years, in years evenly divisible by 4, such as 1988, 1996, 2008 or 2016 (with the exception of century years not divisible by 400, such as 1900) for the Gregorian calendar, which is most widely used in the world today. These are called leap years, and February 29 is the 60th day of the Gregorian calendar in such a year, with 306 days remaining until the end of that year. February 29 is also known as bissextile day or Leap Day.
There is a tradition that women may make a proposal of marriage to men only in leap years, further restricted in some cases to only February 29. There is a tradition that in 1288 the Scottish parliament under Queen Margaret legislated that any woman could propose in Leap Year; few parliament records of that time exist, and none concern February 29. Another component of this tradition was that if the man rejects the proposal, he should soften the blow by providing a kiss, one pound currency, and a pair of gloves (some later sources say a silk gown). There were similar notions in France and Switzerland.