Quite often, I find that my own muse is most inspired by listening to a particular brand of music for the scene I want to write.
For instance, if the scene involves flight of some sort, I want something that's going to have a lot of peaks and valleys in terms of the score (piano music is awesome at that, as is anything featuring a violin/cello). If I'm writing a combat scene, something that gets the adrenalin/angst flowing (most newer rock music, from bands like Disturbed or Five Finger Death punch, work particularly well for me.) It really depends on what I'm trying to write, but I usually find that music motivates me to put my fingers to the keyboard.
Sometimes a really well drawn painting/piece of artwork will do it too, so if the music doesn't work, I hit deviantart to look at concept work. I try to think about what kind of mood I want the characters to have, what I want to set for the reader, where the story is heading plot-wise, how I can blend something unexpected or foreshadow an upcoming event- usually thinking about it for a bit, with music in the background, results in a few thousand words appearing on the screen.
The third source of inspiration for me comes from reading others' work. Sometimes taking a step back from your own writing for a bit and enjoying what others have done lets the muse recharge itself.
