Did you know how leap years came about?

It actually takes Earth 365 days, five hours, 48 minutes and 46 seconds to travel around the sun, a fact the ancient Egyptians first noticed. So an extra day was occasionally added to the calendar, and over time the practice became official.

It was the Romans who first designated Feb. 29 as leap day. Later, a more precise formula (still in use today) was adopted in the 16th century when the Gregorian calendar fine-tuned the calculations to include a leap day in years only divisible by four, i.e., 2008, 2012. Another stipulation ruled that no year divisible by 100 would have a leap year, except if it was divisible by 400. So, for example, 1900 was not a leap year, but 2000 was.

If you were born on leap day on this year, you'd be this old in leap years (and actual years):

1908 25 (100)

1928 20 (80)

1948 15 (60)

1968 10 (40)

1988 5 (20)

Invented at the Savoy Hotel in London on Feb. 29, 1928.

• 2 ounces gin
• 1/2 ounce Grand Marnier
• 1/2 ounce sweet vermouth
• 1/4 ounce fresh lemon juice

Stir and strain into a chilled cocktail glass. Serve with a twist of lemon.

1288 -- Scotland established this day as one when a woman could propose marriage to a man. If he refused, he was required to pay a fine.

1860 -- The first electric tabulating machine -- the forerunner of the calculator -- was invented by Herman Hollerith.

1940 -- Hattie McDaniel was the first African American to win an Oscar, for Best Supporting Actress for her role as Mammy in "Gone With the Wind."

1944 -- Dorothy McElroy Vredenburgh of Alabama became the first woman appointed secretary of a national political party, the Democratic National Committee.

1952 -- New York City pedestrians were told when to walk and when not to, as four signs were installed at 44th Street and Broadway in Times Square. Each sign flashed "Walk" for 22 seconds, then "Don't Walk" for 10 seconds before the "Don't Walk" turned red for 58 seconds more.

1964 -- The United States was in the grip of Beatlemania! "I Want to Hold Your Hand," by the lads from Liverpool, was in its fifth week at No. 1 on the pop charts. It stayed there until March 21, when it was replaced by "She Loves You," which was replaced by "Can't Buy Me Love," which was finally replaced by "Hello Dolly,'' by Louis Armstrong, on May 9, 1964. Fourteen straight weeks of No. 1 stuff by the Beatles.

Sources: Leapzine.com, chiff.com, PG research