Oprah refers to the talk show host Oprah Winfrey.
In 1997, Colonel Jack O'Neill mentioned, jokingly, that he would have to cancel his Oprah interview, because of the secrecy of the Stargate Program. (SG1: "Emancipation")
In 2008, Lt. Colonel John Sheppard created a fake Beer called Oprah Ale to test if the people digging him out of rubble were in fact from Atlantis. (SGA: "Search and Rescue")