In "We Are Family, Part 1", Berk is celebrating Bork Week with the Berkians and their dragons decorating the village with banners, much in the same way as they do for Snoggletog. Later, Gobber decides- as Bork was his great-great-great-grandfather- to present Hiccup with a chest containing all of Bork's Notes and books on dragons, which inspired him to write the Dragon Manual.
Bork Week was celebrated in the game in November 2014 and November 2015, by making the Bork Week Nadder available for search over the span of a week.
The celebrations appear to last a week, and include feasting, decorating the village and general celebrations of Bork's life and work. They generally display Bork's relics as a part of the celebrations, including his dagger and his old notes.