Here in the US, Scanner should be opening at more screens this weekend. Please go see it as soon as you can. I raved about it last week, and now here's an interview and slideshow with the director, Richard Linklater, to add to the pile. Go see it!
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.