I like Neil Gaiman's answer, but even more so, I like the question. Where do you get ideas?
That's a rather good question.
I've talked to a lot of people who are impressed by the fact that I like to write, and they say something along the lines of: "I want to write a book, but I don't have any good ideas,"
The truth may be that I am not exactly a helpful person, because I always say that EVERYONE has ideas, some people just don't know how to get them out of their heads.
I've always had ideas. I remember when I couldn't read, and I ignored words because they meant nothing to me, I would sit in a very small corner between the fridge and the cupboard in my family's kitchen with the biggest picture book we had. I would sit and I would quietly say what I thought the characters in the pictures were saying - complete with different voices for each character. I was making up stories. I was full of ideas.
That's never gone away; it's gotten stronger. I get ideas from many places. These are the one's off the top of my head...
1. In the shower (I don't know why, but showers are amazing for ideas).
2. Folding laundry (again...don't know why...).
3. Washing dishes (SERIOUSLY. I love washing dishes when I'm in a creative rut.).
4. Song lyrics (Who else has written an entire novel based off one song?).
7. Listening to people talk about their lives.*
9. Long walks outside.
10. Single words.
11. Scenes from movies.
13. * Heck, PEOPLE in general.
Every new flower is a story. Every new song is an adventure. Ideas are everywhere. There is no limit to imagination. An idea can come from absolutely anything. I got a story idea from sea monkeys once. I have yet to write that book, but the idea seriously came from sea monkeys.
I love ideas. They blossom from cracks in sidewalks. I once stood on a very small manhole cover labeled WATER and said, "This looks like it could be a time machine,"
See? An idea.
I have this terrible desire to make myself a T-shirt that says "I'LL PUT YOU IN A BOOK SOMEDAY" because every new person is a new idea, who could eventually wind up in another idea, and become a story.
It's very true, what Mr. Gaiman says. Ideas do sometimes just come together like magic in an author's mind. But there's more to it than that.
Ideas are everywhere. You just have to notice them.