This is going to be an area for unfinished, half-thought-through ideas.
So far there is only one - http://www.spodilicious.com/semi-random-scenario-generation.html 

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This, however, is a brilliantly simple campaign system which I found on http://axisofnaughtiness.blogspot.com/2014/11/little-boxes-made-out-of-ticky-tacky.html