Duel Monster Spirit Day is a cosplay Duel Tournament in Yu-Gi-Oh! GX, where people appreciate Duel Monster Spirits. People often dress-up as Duel Monsters on the day. In the dub it is an annual festival.
During Jaden Yuki's first year at Duel Academy, the Duel Spirit, Dark Magician Girl appeared, although many people were convinced it was someone dressed as her. She dueled and was defeated by Jaden.