what do you do in a Demo game?

[TCO]

Is there Civ involved somehow? Or is it micronationalism like At Giant Squid's site?

[GodKing]

We play a single player game of Civ together as a team, with some people focusing on dommestic things and other people focusing on the military and so forth. You learn a lot about the game, meet great people (over the net) and have fun. (this is of course the short version).

[Jon Shafer]

There's also multi-player demo games where all the civs are human teams.