Found through TIGSource, which found it through Fear and Loathing:
This is the binary and source code for Micropolis (A.K.A. “S*mC*ty”: see the GPL License and additional terms, below), which is released under the GPL.
The One Laptop Per Child laptop is going to have an official and original SimCity game available for it. Don Hopkins has cleaned up the code and removed references to the SimCity trademark. Now the source to the original SimCity is available for everyone to study, play with, and change!
The key thing here is to peek inside the mind of the original Maxis programmers when they built it. Remember, this was back in the day when games had to fit inside of 640k so some “creative” programming techniques were employed. SimCity has been long a model used for urban planning and while it’s just a game, there are a lot of business rules, ecosystem modeling, social dependencies, and other cool stuff going on in this codebase. It may not be pretty code but it’s content sure is interesting to see.