You are getting sleepy, very sleepy. When your head hits the pillow itís lights out for the brain and body, right? Not if you consider the brain cells that must fire to produce the sometimes vivid and sometimes downright haunted dreams that take place during the rapid-eye-movement stage of your sleep. Why do some people have nightmares while others really spend their nights in bliss? Like sleep, dreams are mysterious phenomena. But as scientists are able to probe deeper into our minds, they are finding some of those answers. Here's some of what we know about what goes on in dream land.