THOUSAND OAKS — What began as a golf game conversation in the early 1970s, has become the largest Nordic festival in Southern California. The Scandinavian Festival — the legacy of the late Professor Armour Nelson and the late John Nordberg — will celebrate its 50th anniversary on May 18 and 19. Held at California Lutheran University in Thousand Oaks, the family-fun festival honors the founding of the university and the history of the Conejo Valley, which Norwegians settled in the 1890s.