Believe it or not, it appears that humans were making maps several millennia before the existence of written language. A map of the stars found on the walls of the Lascaux caves dates back to 16, 500 B.C. In fact, most of the earliest maps were of the night sky.
Now we have a plethora of well-known map sub-categories: there are topographic maps, geologic maps, nautical charts, weather maps, linguistic maps, etc. Well know you can add another category of maps to your list: strange maps.
Strange Maps is an awesome blog that serves as an odd, catrographic compendium of information. Some highlights include a map where U.S. states are renamed for countries with similar GDPs, the secret soviet plans for the complete removal of the North American continent, and the world in George Orwell's 1984.