My best ideas always come at the most inconvenient times - I think I may have mentioned this in my entry about the voice recorder on my phone. I know part of this is because these times are when my brain is the most relaxed, but that doesn't make it any less frustrating to have a good idea and forget it before I can write the details of it down.
My best ideas come in either the shower, the car, or in that hazy place between waking and sleeping, after I've turned off the light for the evening (as the Arcade Fire says, "between the click of the light, and the start of the dream"). The shower's not such a bad place, because I can get to my computer or paper and pen fairly quickly, so I won't lose much of the idea. Same goes for being in the car, especially now that I've realized I have a nifty voice recorder on my cell phone. As I'm falling asleep, however...
That dreamy, half-awake-half-asleep span (I read somewhere it takes the human brain about seven minutes to shut down and unplug all its connections to the "real" world) is always the time I get the absolute best ideas. I think a large part of it comes from my brain being so relaxed and allowing everything to flow through it at once, instead of struggling to sort thoughts and impulses into their proper pigeonholes (one of the hallmarks of ADD is learning to compartmentalize every idea as it comes). My thoughts hover between imagination and dreaming. I think it's interesting how the two states are so similar, yet the former is conscious-driven and voluntary while the latter is powered by our lower brains and we have no choice of what we dream about. At the point of sleep taking over, my imagination sometimes melds with my dreaming brain and I start dreaming about my story.
Often in years past I'd have a good idea and, just before falling asleep, convince myself I'd be able to remember it in the morning. I'd spend the last few seconds of waking concentrating as hard as I could on the idea, so it (in theory) would be the first thing I thought of when I woke up in the morning. This tactic rarely worked. More often than not I would remember I'd thought of something... but I'd have no idea what the details were. Such a frustrating feeling.
Sometimes I'm able to fend off sleep long enough to sit up and jot down a few notes, which is why I keep a pen and pad of paper near the bed. And then sometimes what happened last night happens... I turn over, reach down, pull open my laptop, and engage in a bit of sleepwriting.
Last night as I was passing out, I was hit with a vision of perfect clarity: my antagonist, standing in the grocery store with her hand on a can of beans, listening to a voice in her head. It was so perfect I could even see the label on the beans and hear the stupid muzak pouring out of the overheard speakers. I couldn't shake the vision, so I shrugged off sleep for a moment and took advantage of the clarity in my mind.
I carved out about 400 words, which isn't much, but I don't remember writing a bit of it. I went back and read it this morning am pleased with the result. Not only did I get down the idea which had popped into my almost-sleeping mind, I'd managed to fluidly work it into the current scene. It was fun to read back over, too. Kind of like a letter from my subconscious. I guess it's little scenes like that which help me know I'm still on the right track with this story, over all the months, words, and pages spent on its creation.