Christopher Nolan’s Inception, opening this week, promises to be another leap forward for one of pop culture’s greatest devices: the dream sequence. The film pioneer Georges Melies filmed the first such sequence around the turn of the century, which means that it predates the close-up and even, to some extent, film editing. Over the decades, of course, we’ve gotten lots of dreams in movies and TV: From goofy ones that last a few seconds (think of any Family Guy episode) to entire seasons of TV shows that turned out to be dreams (think Dallas). The popularity of the dream sequence, however, belies the device’s many pitfalls. Here, then, are our ten rules for creating a dream sequence, paired off with the movies and shows that illustrate them.