Comment with two fandoms that I am either in or that you know I follow/know about to some extent, and I will tell you whether I think they could cross over, and how that might happen. (I'm not writing the fic though. *g*)
OR
Comment with a link to your favorite piece of fan fiction. This can either be your personal favorite, or what you consider to be the *best* piece of fanfic you've ever read. It can be from any fandom, even ones I don't normally read, but if you link to slash or incest or non-con, I'm not going to read it, so do take that into consideration.