Came home from work last night and Terminator 4 was on TV, so I watched it and it reminded me of an idea I'd had a couple years ago, formed when I'd heard they were making the next Terminator movie to take place during the War Against the Machines.
I had the idea that Star Frontiers would actually make a fairly good, simple system to run a War Against the Machines campaign. Strip out the Yazirians, Vrusk and Dralasites. Start the PCs with limited technology, but Skynet has access to everything in the book. Robots are pretty tough opponents in that system (and easily customizable), and the skill system is designed primarily around combat and secondarily around exploration. You really don't need much else for a post-apocalyptic non-scifantasy setting.
My grand idea was to allow the players to play a bit of a metagame, managing the resources of their survivor community--population, supplies, tech, and then have the PCs missions affect those community stats. Rescue some prisoners of Skynet and your population increases, allowing you more "credits" (which would be abstract rather than hard currency as in the normal rules) to purchase gear for missions. Raid the right Skynet factory, and you suddenly open up gyrojet or sonic weapons as available to the PCs. Stuff like that.
I think it could be a fun game, but finding players for it, and my own ability to keep interested in it might be tough.