Betty Webb's blog post on "Method Acting for Writers" has some good points to consider when developing characters for your stories. She had written a character into her story that didn't fit. So she thought about how to increase the suspense and interaction and ended up pounding away on the keyboard and not remembering anything about it with the idea that popped into her head. Her husband told her it was "an out of body" experience.
But what she really did was fully immerse herself in the character, becoming the character in her mind's eye and everything fell into place. That's why she couldn't remember it. I've had a similar experience on a couple of occasions and was thrilled with the outcome, and wondered where did it come from? I am sure that these experiences are prevalent throughout the writing community.
Check out Betty Webb's blog at bloggingwebb.blogspot.com for her take on this phenomenon.