Sean and me spend the world wide launch of civ5 with a MP duel (and some waiting for the game to actually be available ).
We played Egypt vs. France on duel sized Inland_Sea. It was quick game speed and in an attempt to keep land fair(er), we used legendary resources.
Here is a description of the game from both sides.
There are a couple of other as well, like North-vs-South.
Just go to Multiplayer -> Lan Games and attempt hosting a game and youŽll see which maps are available at the moment.