The first time I tried this I was trying to come up with the plot and asking the computer to write sentences.
Computers suck at writing good sentences.
TVtropes.org is pretty much the bomb; if you've been there you know what I'm talking about. The community has done all the hard work cataloging what must be thousands of tropes, each one a specific element of narrative.
So, I'm taking advantage of all their hard work. I've already built my little recombo engine for the back end, now I just need to do the ui and data entry, and I'll have a little story, complete with multidimensional characters and an interesting plot, and all I'll have to do is the (extremely fun) work of fitting them together with good sentences.