The Gregorian reform of the Julian calendar introduced an extra day to make up the difference, with leap years of centuries divisible by four skipped. This still needed tweaking: By 1582, with 11 minutes a year left unadjusted, the calendar had shifted 10 days. In 46 B.C., Julius Caesar noticed the calendar had fallen behind 90 days and tried to correct the difference, and added days here and there to months on the calendar for one year, adding a leap day every four years thereafter. Leap-year days serve a purpose, as we know: The extra day tacked onto the end of February every four years accounts for Earth’s spinning around the sun five hours, 48 minutes, and 45 seconds longer than 365 days. We mark time between real birthdays in fourths and halves. Leapsters keep two sets of ages, annual and quadrennial. She gave them each state-of-the-art digital picture frames. “I think you’re all so lucky!” Stewart said, sort of sincerely. They wore frog-mouth name tags (frogs leap, get it?). Back in 2008, Martha Stewart hosted 200 leapers on her show. News reports in secondary markets sometimes feature leap-day births or an octogenarian leaper’s 20th. We leaplings, as we’re called, have defied 1-in-1,461 odds to have our birthdays fall on February 29. For 187,000 of us in the U.S., that’s what happens three-quarters of the time. That’s a birthday’s job: You turn a year older, whether you blow out the candles on the cake or not. Here’s the thing about birthdays: They happen each year. Emily in Paris Is the Last Guilty Pleasure Spencer Kornhaber

Frog leap year