Today, Friday, Oct. 5, marks World Smile Day. How did this unofficial holiday begin?

The ubiquitous smile design, plastered on everything from t-shirts to buttons, was conceived of by Worcester, Mass., artist Harvey Ball in 1973.

But Ball was worried about “the over-commercialization of his symbol,” and World Smile Day began in 1999, according to worldsmileday.com.

Ball “thought that we, all of us, should devote one day each year to smiles and kind acts throughout the world,” the official World Smile Day website says. “The smiley face knows no politics, no geography and no religion.  Harvey’s idea was that for at least one day each year, neither should we.”

Ball, who died in 2001, declared World Smile Day be held on the first Friday in October, and the tradition has continued through his Harvey Ball World Smile Day Foundation.

“We celebrate World Smile Day each year to focus attention and help us recall the original ‘mission’ Smiley had, that was to reflect what we all hope to see in the face of others – a SMILE,” the website said in its World Smile Day 2012 Message. “Smiley helps us remember and use the power of a smile.”

In Ball’s hometown of Worcester, World Smile Day was celebrated through performances by Ringling Brothers & Barnum and Bailey Circus. Free World Smile Day merchandise was also distributed to those who attended the Worcester event.

For those who were unable to take part in the festivities, the World Smile Day website is helping you celebrate the day by printing out an 8-by-10 poster related to the occasion. The website also featured a black and white version of the poster so kids can color their own World Smile Day poster.

The website has a section on how to become a World Smile Day ambassador – whether it’s through spreading the world about the occasion or coming up with your own ideas on how to get others to smile on Friday. The section had more than 100 comments as of Friday afternoon.

“We are celebrating in my work today. We have posted notices throughout the building encouraging people to smile. We are having a ball so far. People are not only smiling but they are also laughing,” wrote T. Greeley. “The mood is AWESOME!!!”

“Today my neighborhood children are having a bake sale to raise money for cleft palate surgeries through [charity] SmileTrain whose motto is ‘Changing the world one smile at a time,’” shared Kendra Kullgren.

“I didn't know about this until today. I am passing the poster to all the staff and students so they can share today's purpose,” wrote a teacher who only identified herself as Miss Trudy. “They will all try to do an act of kindness and make someone smile today.”