In modern times, it's a little outdated to think women need a specific day to propose – but for those that want an extra reason, a leap year has long been the year 'women can propose to men'. Proposing, for centuries, was the gentleman's prerogative, but once every four years Leap Year tradition dictated that on the 29th of February, women looking to put a ring on it can ask their loves to marry them.
Where did the tradition begin? Supposedly Ireland in the 5th century. Saint Brigid of Kildare, arguing that women were languishing away waiting for their shy beaux to pluck up the nerve to pop the question, asked Saint Patrick to give a day they might do the deed themselves. A little haggling was involved, with Saint Patrick first suggesting every seven years, but eventually the Leap Year was settled on. According to folklore, Saint Brigid then immediately proposed marriage to the Irish saint.
As the Irish nun would have been around nine or ten years old when St. Patrick died in 461 A.D, this story is a little dubious, but no less charming for it.