I am new to the whole soundboard thing, but the people over at unrealisticexpectations have a whole lot of really good ones. If you are ever jonesin' to hear Ralph Wiggum say "My cat's breath smells like cat food." or Bruce Campbell discussing his BOOMSTICK, I would suggest you go there.
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.