Short answer: Every four years, in the same years as American presidential elections and summer Olympics. Longer answer: Almost, but not quite, every four years. Need a news break? Check out the all ...

Thursday is a leap day, the rare date of February 29 that's added to the calendar nearly every four years. That means the roughly 5 million people worldwide born on that day — aka "leaplings" — will ...

Each year has 365 days. Well, almost. Every four years (give or take), our calendars receive an additional day. So, as you're making leap day plans for this year, here's a quick primer on how it came ...