High Quality Content by WIKIPEDIA articles! "They Saved Lisa`s Brain" is the twenty-second episode of The Simpsons` tenth season. It first aired on the Fox network in the United States on May 9, 1999. After writing a thoughtful letter to the Springfield Shopper, Lisa is invited to join the Springfield chapter of Mensa. When Mayor Quimby later flees Springfield, the group takes control of the town, hoping to improve the lives of Springfieldians through the rule of the smartest.