As Eleanor mentioned, I get some of my ideas from dreams. I thought it might be interesting to talk about that at least a little bit more both in terms of story development and why I think this happens. I have very vivid dreams, but only if I'm between writing projects or it's been a couple of days since I've written.
This is either a subconscious manifestation of something my wife calls "leaking weirdness," or leaking weirdness is a conscious manifestation of the subconscious phenomena. In either case, if I go for more than a couple of days without actively working on my fiction, I start to get a little strange. The longer I go, the stranger I get, and the stranger I get, the more frequent are Laura's suggestions that I "go write something and get it out of my system."
Basically, as far as I can tell, I need to tell stories, to invent new worlds and people and share them. If I'm not working and I can't get them down on paper, they start to leak into my dreams and out of my mouth, especially first thing in the morning. This has led to such bizarre leaking weirdness ideas as llamoflage, and Robert the Bruce Springsteen-you can take our lives but you canna' take our guitars.
It has also led to some of my better story ideas on both the dreams front and in terms of leaking weirdness. Basically my brain, seemingly independent of my conscious will, starts to put things together that might not normally go together, like goblins and laptops in WebMage, or food fights and the twilight of the gods in the short story FimbulDinner.
One final note on process, and then I'll end this ramble. The ideas I get from dreams almost never come complete and coherent. I'll get one really striking image in a big mish-mash of dream-story that resonates for me. Then, when I wake up, just past the edge of dreaming, I'll try to identify what's so cool about that image by telling myself a story about it, filling in a background and future developments that were missing in the dream, and converting impression into narrative in a very conscious way. The dream provides the seed, but I have to plant it and nurture it arrive at something that's worth sharing with others.
So, as Eleanor asked, where do you get your ideas? Do your dreams whisper narrative in your ear? Do billboards mix with Celtic mythos and drink recipes in your waking mind? What makes you a writer of the fantastic?