The International Sweater Vestival is celebrated worldwide on December 01, 2017 . On this festival people are encouraged to wear sweater vests to work, and if they are in the lucky position owning more than one sweater vest, to bring them to work too and share the vests with less fortunate coworkers who doesn't own one. The inventor of this holiday is unknown. The Sweater Vestival was first mentioned in by Carolyn Johnson for the Boston Globe in 2008. Carolyn never disclosed the identity of her interview partner.