June 6 — same date every year
Yo-yos date back at least as far as ancient Greece. A Greek vase from 500 BC shows a boy playing with a yo-yo:
Yo-yos became popular in America when Donald F. Duncan manufactured the Duncan Yo-Yo in the early 1900s. His birthdate, June 6, is now celebrated as National Yo-Yo Day. He was born on June 6, in Kansas City, Missouri, died on May 15, 1971 in Palm Springs, California.
Social media hash tag: #NationalYo-YoDay