People often ask this of writers...right before they tell them about an idea that they have to write. It's the cutest thing. And then I explain that ideas are not the issue, time to write the story is!
Today was a fieldtrip with HappyBoy's class to a Forest Center. As we were hiking around enjoying the nature (and the Oregon drizzle) I kept noticing something.
They were everywhere, dozens of different kinds. Fascinating. And that, my friends, is where I get my ideas. They usually spring up from nowhere.
At some point, I'm going to have a character who knows about mushrooms, because now I'm curious.