I keep a notepad by my bed in case I have a stellar dream and just have to write down something that might be good for a story. Sometimes I wake up and see that I've actually written down something fun in the night. Other times I wake up, look at the pad and see something like ASPARAGUS! written in a bold scrawl and I wonder if it was just a really bad case of indigestion.
Last night I dreamt about a girl searching for her family. In her journey, she went into an antique store. The proprieter took her to a wall that was filled with doorknobs of all kinds. The handles were anything from simple brass to painted china. One faceted glass knob seemed to glow and I knew that if she chose that knob it would take her somewhere special. I woke knowing that it could be the beginning of an intriquing adventure if I could wrap my head around it. It made me want to go back to sleep.
In an interview, Stephanie Myer says that her book Twilight was inspired by a dream. Who knows, it could happen.