Where do ideas come from?

People have asked me often where do I get my idea for a certain book. How do I come up with so many? Usually something will trigger my excitement. I will think about it and a story will begin to form in my mind. It can be something like a profession–example the arson investigator in Gold in the Fire was the beginning of that book. In another it might be a location–example the jungle in my Love Inspired Suspense (yet unscheduled) Heart of the Amazon. I am fascinated with the rain forest and enjoyed placing a book there. Then sometimes it will be a problem that a person faces–example bullying is used in the book I am writing right now, my last one in the Sweetwater Series, Tidings of Joy due out next October. I work with high school students and have seen the effects of bullying with kids. Or, lastly it can be a situation–example: what happens when you witness your brother’s murder and end up running for your life?
What prompts your ideas when you write?