The idea of holidays in setting is really fun, and I know I should do them for flavor, I just haven't had many good ideas lmao. Old Bariuran holidays could be pretty funny too, idk how many the succs would know but one or two maybe.
Explaining a modern Hieroneidan holiday named after some ancient crusader would be kinda funny too. Sorta like christmas, where the 'santa' thing got added in later.