With February 29th approaching, here's some (somewhat) interesting facts:
A Leap Day is technically called "Intercalary Day".
A true solar year is 365.2422 solar days. So it isn't exactly 1 day every 4 years different. So to keep things in synch, every fourth year, meaning every year whose number is evenly divisible by 4, is a leap year and is granted an extra day—that is, except for every 100 years, when we skip the leap day, except for every 400 years, when we reverse the rule and add a leap day once again. So the years 1700, 1800 and 1900 were not leap years. The year 2000 was because even though it’s divisible evenly by 100, it’s also evenly divisible by 400. The year 2100 will not be a leap year, but the year 2400 will be, and so on.
You will truly be the life of the party when you break this one out.