In 1977, in the very early days of digital watches, I bought one with red LEDs where you had to push the side button to turn it on...one push for time, two pushes for date.
One day I was helping a friend do some work when I wanted to check the time until lunch...pushed the button and got 11:11


?? says I. Pushed it twice and got 11:11


Is this watch already broken, I wondered? Pushed it several more times... same result: 11:11


Then it hit me... it was 11:11 AM on November 11!