THE SIMPSONS Season 12 Episode 10 : Pokey Mom
The family attends a prison rodeo and Marge sees artistic potential in one of the inmates after she sees some of his work hanging in the prison infirmary. She volunteers to teach art at the prison and then vouches for her artistic inmate at his parole hearing. Now back in the real world, the inmate needs a job and Marge gets him one at the school, painting a picture depicting school spirit. His take on school spirit and Principal Skinners are at odds. Meanwhile Homer, whose back was injured at the rodeo, seeks the help of chiropractor. He soon discovers that his old trashcan is just as effective as the chiropractor, so he dubs it "Dr. Homer's Miracle Spinal Cylinder" and goes into business for himself. Until the chiropractors take their revenge.