That's a hard question. I don't really "get" them; they just kind of come to be.

One way for good ideas are dreams. Dreams are great places for ideas. I keep a journal filled with crazy dreams, and the more I write in it, the more vivid and creative they get. Twilight came from a dream.

You can get good ideas from maps, too. One day, I was bored and drew a city. I still check up on it every now and then, and the characters just sort of form from the setting. I learned this trick from Orson Scott Card.

Myths and legends are great idea-helpers, too. There are so much you can do with them, whether they are well known (Like many Greek Myths) or obscure (such as ancient Irish or Native Amerian tales).

My ideas? I don't know. Often I'll just see a character, or hear their voice, and the story will go from there. But a lot of ideas come out of nowhere.