One of the main inspirations that gets me going when writing is music. Whether it be soft and melody-like or a hard rock song from the 80s, this has been one of my go-to's when I can't figure out what to write.
Sometimes I will go to bed early just so I can lay in the dark, close my eyes and turn on my iPod - then I let my imagination flow. I even have a playlist on my iPod called "Inspire for iPod" (no joke). When I'm going through the gazillions of songs on my iTunes, or if I hear a song on a commercial or the radio the sparks a little something, I download it for future inspection.
This has helped me IMMENSELY with writing, especially the huge 3-part novel that I'm writing with my BFF. It's the longest piece of fiction I (or we) have ever written and music has played such a big part in it that whenever I hear a certain song I will instantly relate it back to a certain scene in the story.
For example: There's a slow, ominous song that I like and one night I was listening to it while laying in bed (Lucky You by Deftones), and I just try to "feel" the music (Ok, that may sound weird, but stay with me). Whenever I'm writing, probably 95% of the time I picture what is happening inside my head, almost as if it was a movie in my mind. As I listened to this song I could picture the exact way the characters were moving or talking, and it also made me think of grand ideas to go with. If you think of an idea you want to portray in your writing, grab some tunes and almost guaranteed you'll find a song that will match the mood of that scene and it almost boosts your imagination to think of how this scene will play out, or even spark ideas for what will happen before/after.
If I'm ever stuck (writer's block *cough* *cough*), I'll listen to songs that I know will relate to something in the story, whether it be a sad scene, intense scene, hate/fight scene, sex scene, etc, etc, and if I just listen to it a couple time your mind will relay what you want to happen and, in my head at least, plays out like a movie scene. Afterwards, when it comes to write that part (sometimes I'll know what can happen MUCH later in the story, just because I hear a song and know something will happen from it), I play the song and the reel starts going in my head, then transfers to paper (or computer screen).
All in all, music plays a HUGE part for me with plot ideas, inspiration, sparking the imagination, or even just something to have on in the background to relax so I can write.
As a special treat, here are a few songs from my iPod playlist "Inspire for iPod", that have really helped me out with scenes in my writing.
Apocalypse Please - Muse
Goodnight Boy - Arcade Fire
Asleep from Day - The Chemical Brothers
Change - Deftones
Crazy on You - Heart
Comfortably Numb - Pink Floyd
Eden - Hooverphonic
Fade into You - Mazzy Star
Hide and Seek - Imogen Heap
Lie in the Sound - Tresspassers William
Roads - Portishead
The Scientist - Coldplay
Heroes - David Bowie
Lucky You - Deftones
Sympathy for the Devil - The Rolling Stones
Time to Pretend - MGMT
Within You - Ray LaMontagne
Wake Up - Arcade Fire