I have to admit that I've never been much of a SimCity fan though of course I know plenty of people that were addicted to that game at one point or another. The latest twist in SimCity land isn't a new mod or expansion back but is the open sourcing of the SimCity source code itself..not the latest/greatest version mind you..but an older version.

Due to copyright issues the open source version of SimCity isn't called SimCity either - instead it's called Micropolis - and it's being released under the GPL.

The developer that is releasing the open source version of SimCity, Don Hopkins has also made it available as a game for the One Laptop Per Child (OLPC) effort.

"Micropolis" is the name of the current GPL open source code version of OLPC SimCity. That was the original working title of Will Wright's city simulation game. Since Micropolis is licensed under the GPL, anyone can do anything they want with it that conforms with the GPL, except they can't call it "SimCity" (and a few other limitations to protect EA's trademarks).

Micropolis is a dreadfully basic game and so far as i can tell it's based on something that i might have considered to be 'abandonware'. Then again it was and is a fun game and who knows maybe someone  will be able to expand it under the GPL into something more than it is.