June 6 — same date every year
Yo-yos date back at least as far as ancient Greece. A Greek vase painting from 500 BC shows a boy with a yo-yo.
Yo-yos became popular in America when Donald F. Duncan manufactured the Duncan Yo-Yo in the early 1900s. National Yo-Yo Day is celebrated on June 6 — Duncan’s birthdate — born June 6, 1892, Kansas City, Missouri, died May 15, 1971 Palm Springs, California.
Social media hash tag: #NationalYo-YoDay