"My World" is a prime example of what fun a lazy GM can have with maps of the Earth. The name of my world is "Terra Ursa" and as of right now, there are three major places being defined there.
in location one, the area on the Earth map that usually coincides with North America is where my first and original campaign started out. It has been on the back burner for awhile now as the Players have been exploring the other two locations created afterwards. Basically, where each of the U.S. states would be, is a small country that has it's own unique culture, politics, etc...
The Great Plains states seem to currently represent "general" medieval lands. The Eastern side consists of lands from literary backgrounds such as "Poeland" and a land based on the works of H.P. Lovecraft and others to be planned.
Location two is made up of the place people refer to as "Middle Earth". The Players have been adventuring in Middle Earth for months now and are really liking it a lot. Middle Earth takes the place of Europe and Asia on the Earth map.
Location three is now the place where our third and most recent campaign takes place for the Gladiator Games. I have finally decided that the Gladiator Games takes place on what would be Australia on the Earth map. The Caesar who rules there rules over the entire continent. There are several arenas there in various cities that the Caesar travels around to as often as he can (he lives for the games) but the games travel and go on even when he is otherwise occupied.