The theme is \"Fun Makes a Comeback,\" and opening day is Friday, Aug. 25, with a smorgasbord of animal exhibits, carnival rides, competitions, concerts and food planned during the 11-day event that is scheduled to run through Sept. 4. Oregon State Fair is the official fair for the state of Oregon. It takes place every August–September. At the event you can enjoy concerts, animals, carnival rides, competitions, food, fun and more.