Where Did You Get That Idea?

One of the questions I get most frequently from non-writers is 'where do you get your ideas?' People are fascinated by the idea of making up stories from nothing – and being able to do it again and again. My personal favorite answer to that question is from Susan Elizabeth Phillips, one of my favorite authors. When someone asks her that question, she smiles and says, 'from a warehouse in Tulsa.' Although I wish I was as quick and clever as Susan, my usual answer is an uncomfortable shrug and an 'uh, they just sort of come to me.'
Most of the time, that's the best I can do. An idea might be triggered by something I read in the newspaper, or a snippet of a conversation I overheard at a restaurant or store. Yes, all you non-writers out there, be careful. Writers love listening to other people's conversations. There's nothing as fascinating as other people's lives. This is, perhaps, because our lives mostly consist of sitting in front of a computer and staring into space.
But I digress. When I can actually pinpoint where the idea came from, I remember it forever. My March Superromance, For Baby and Me, is one of those books.
A couple of years ago, when I had to get downtown early on a weekday, I took the commuter bus from my neighborhood to the train station. It was very early – around 7 AM – and I hadn't yet had my caffeine hit. So I was sort of bleary-eyed, and when the bus arrived, I plopped into the first seat I saw. Sitting across from me was a very pregnant woman.
I immediately began wondering about her – where she worked, if she had to walk from the train station into the Loop (a good six or seven blocks), if she had other kids at home, etc, etc. From there, I began to wonder other things – did she like her job and was she looking forward to her maternity leave? Was she a single mother? If so, did she have family in the area, or was she completely on her own? You writers know how that goes. I just couldn't help myself.
The questions lingered, and they eventually morphed into Sierra and Nick's story in For Baby and Me. I wish I could thank the woman, but I never saw her again. I would have liked to tell her that her baby sparked the creation of my baby.
Writers, what do you tell people when they ask where you get your ideas? Do you wish there was a warehouse in Tulsa? Readers, what in a story draws your interest and sucks you into a book? I'll enter everyone's answers into a drawing for my last two books, Can't Stand the Heat? and Life Rewritten (I know where that idea came from, as well. Two in a row!).