I am not sure how many of you are familiar with S. M. Stirling but i picked up a book of his yesterday called Dies the Fire. Its part of triology set during 1999. Its post-apocalyptic in setting, but is not what you are thinking. Some unexplainable thing happens that renders anything electronic useless. Engines, electronics, pumps, everything! Gunpowder and explosives dont work either. What ensues is utter chaos. 747 fall out of the sky, causing widespread damage and death especially over major cities. Everything taken for granted is gone. People in cities suffer the most, people turn to canabalism. Some people start to form their own communities. Small farming towns are the best off, but millions of people are going hungry. A few people take iniative. Gangs are consolidated into armies using medieval aged weapons and armor. They steal from those that have it. etc etc.
I read about 200 pages of the book yesterday and its inspired me to tinker with the idea of running a game along those general lines. Any takers?