There seems to be a misunderstanding, as there is no specific "Crown Princess Mette-Marit's Day" celebrated in Norway. Crown Princess Mette-Marit is the wife of Crown Prince Haakon, the heir apparent to the Norwegian throne, and while she is a well-respected member of the Norwegian royal family, there isn't a public holiday or specific day set aside to celebrate her in the Norwegian calendar.

However, like other members of the royal family, Crown Princess Mette-Marit does participate in various national events and celebrations throughout the year. This includes National Day on May 17th, which is a significant public holiday in Norway celebrating the country's independence. On this day, Norwegians typically engage in parades wearing traditional outfits (bunad), attend community events, and enjoy festivities with family and friends.

Crown Princess Mette-Marit also takes part in other royal duties throughout the year which may include public engagements, cultural events, and charitable work. Her activities on any given day would largely depend on her official schedule released by the Royal Court.