When i hit a rut, I either try to find new music and listen to it. Or listen to genius original music by someone else. I was in a rut recently and listening to Making Mirrors album by Gotye thru headphones just totally inspired me. Also, sometimes i pretend the bass is another instrument and play brass type phrases. And finally i'll ask the band to indulge me and just go crazy and practise playing all kinds of mental sh*t just to break down creative doors, so to speak!