Leap Day is Feb. 29, which only happens every four years during a leap year.
Adding a day to the calendar every four years keeps it in sync with the solar calendar, measuring the Earth's trip around the sun.
Number of people born on Leap Day: 4,791,239
Number of people born in the U.S. on Leap Day: 10,800
Famous people born Feb. 29:
-- Pope Paul III
-- Motivational speaker Tony Robbins
-- Actor Alex Rocco ("The Godfather")
-- Actor Dennis Farina
-- NHL goalie Cam Ward
-- Singer Dinah Shore
-- Bandleader Jimmy Dorsey
-- "Parks and Recreation" character Garry (Jerry, Larry, Terry) Gergich
For more information on leap years, go to leapyearday.com.