1. On October 20, 1910, the Oklahoma Historical Society was established. It was founded with the aim of preserving and sharing the history and culture of Oklahoma. Today, the organization operates the Oklahoma History Center and maintains archives, museums, and historic sites throughout the state.

2. In 1973, the American Indian Exposition opened its doors for the first time in Anadarko, Oklahoma. The event celebrates Native American culture and features art exhibits, dances, and other cultural demonstrations. It remains a popular attraction to this day.

3. On October 20, 1977, singer-songwriter Jimmy Webb was inducted into the Oklahoma Hall of Fame. Webb is known for penning hits like "By the Time I Get to Phoenix" and "Wichita Lineman," and is widely considered one of the greatest songwriters of his generation.

4. In 2003, the Oklahoma City Thunder played their first-ever regular-season game against the Houston Rockets. Although the Thunder lost that game, the franchise has since become a perennial playoff contender, with multiple appearances in the NBA Finals.

5. On October 20, 2018, the Oklahoma Sooners defeated the TCU Horned Frogs in a college football game. The Sooners went on to have a successful season, finishing with a 12-2 record and a spot in the College Football Playoff.