All. The. Time. I think I've said it before, in another thread, if it isn't a real life experience, or a song, my inspiration is usually a dream.
My very first example was when I was still a little kid living in Chicago. I had a dream that was so vivid, and I thought, had such a cool story, that I wanted to see the story finish when I woke up. So I started making up my own story to how that dream would end. I'm pretty sure that was the catalyst for me writing.