Cool idea! And my girlfriend used to play Civilization 3 and then 4 all the time. Now she's playing WoW (since about three years ago). We've been married for over 23 years now.
As far as your party, I think the cake should be a stylized map, with miniature wonders on it (you should be able to find little plastic "wonders" somewhere). Another idea would be to serve some drink that is a blue liquid (Kool-aid?) in beakers (or beaker-shaped glasses). Of course, setting up a big screen to play the game so attendees can be "part of the action" is a must. And play the CDs with the game music on the stereo for background music You do have those don't you? They came with the deluxe version.
Oh, and only allow ON PEROSN PER TILE <grin>.