Ward Shelley created a beautiful History of Science Fiction graphic. It may be turned into a poster.
“History of Science Fiction” is a graphic chronology that maps the literary genre from its nascent roots in mythology and fantastic stories to the somewhat calcified post-Star Wars space opera epics of today. The movement of years is from left to right, tracing the figure of a tentacled beast, derived from H.G. Wells’ War of the Worlds Martians.
Visit his site to see the image full-size (sample below).