Yeah, I just read about that. They have a mod to play offline though. Civilization V maybe? Never played it before. Can anyone shed a light about the game? From the looks of it, it's like Simcity, but with enemies and other region agreements? Sounds interesting.
They're quite different. For starters, Civ 5 is competitive and a game has an ending (although you can play indefinitely) and a winner. Simcity 4 has no defined objective and no victory conditions. Civ 5 is a turn based game, while Simcity 4 isn't.
In Simcity, you play as a dictator/mayor in charge of a city. You zone areas for residential, commercial, or industrial use, provide utilities and services, set tax rates for different income levels and types of industry, decide how much funding to allocate to different departments and utilities, build roads and highways, public transit, etc etc. It gets complex pretty fast, and it's fairly daunting to new players to have so much to manage.
In Civ 5 you're once again the dictator except you're in charge of an entire civilization of people. You start off with one city in the Ancient age (4000 BC), and grow your civilization over the years into the year 2050. You can win by being the last player controlling your original capital city, by becoming a social utopia (or becoming a world famous tourism spot in the newest expansion), building a spaceship to send to Alpha Centauri, being voted the head of the UN, or by having the most points in the year 2050. At the highest difficulty settings the game is full of micromanaging and is incredibly complex, but at the "normal" difficulty or easier it's pretty simple to start playing and figure it out as you go.
Both games are excellent and will suck hours of your time away if you're not careful. Civ 5 is particularly addicting, because things happen on a timescale of turns, so you can easily get caught into the trap of "oh just one more turn until I research flight, I can't quit now!"