As well as a line from the opening to "Defenders Of The Earth", this is the name of a Civilisation clone by SidMeier. It's rather fun, actually, as all SidMeier's games are.
Hang on. Can you actually have a CLONE by SidMeier? Wouldn't that be like saying Peter Molyneux made a populous clone?
Yes. Because games not of the civilisation family (by which I mean Civilisation?, Civnet, Colonisation?, Civilisation II, Alpha Centauri and Civilisation III) are still clones, irrelvant of who made them. But I'd just refer to it as a 4X game (which it is, and an impressive one at that) rather than a clone and be done with it.