The One Laptop per Child project will soon release a free software version of the classic SimCity game. The company agreed to publish the code under a GPL-license. It'll however contain a clause that modified versions are not allowed to be named SimCity, else it's completely free software.

I think that's great news and would welcome it if more classic games could be freed. Computer games are their own form of culture and we need more projects to protect this kind of culture.

SimCity at the OLPCWiki