It takes the Earth about 365.26 days to go completely around the Sun once. The 0.26 of a day causes a problem for the people who design calendars. If they don't make allowances for that difference, the dates on the calendar and the real seasons will soon drift apart. The solution is to add an extra day to the calendar every 4 years. That extra day is called a leap day (閏日). A year with an extra day is called a leap year (閏年). 2012 is a leap year. Today is the leap day. Happy leap day!
Traditionally, a man should propose to his girlfriend. (To "propose" means to ask someone to marry you.) In Ireland, it's a tradition that a woman can propose to her boyfriend on a leap day. If you're tired of waiting for your boyfriend to ask you the big question, you can propose to him today. Good luck!