If you have a local TV station that broadcasts on Channel 6, try tuning your radio to 87.7FM. I regularly listen to the Simpsons on a Fox station on my way home from work. Even though I know most episodes by heart, the Simpsons can throw so much at you at one time that you miss things. I now realize how much the audio track contributes to that show, over and above just the dialogue. At lunch, I can also listen to the various Judge shows and the Feud.
*Update 4/24/2011. With the advent of digital TV, this is no longer the case.
I have found it helpful to do the stretching exercises my physical therapist recommends. Do some core strengthening exercises, such as the ones highlighted at The Mayo Clinic. By keeping your core strong, your back won't put itself in a position to cause that sciatica pain you are having.