As far as the unique storyline question, it could be any kind of story. The one that came to mind first for me is my short story Hybrid, the killer monkey one I wrote for the April Fool's challenge a few years ago. It was a sci-fi, which is not a genre I usually write it, and I wrote it in present tense, which is also not how I usually write, so that made it really unique for me.
If we're talking novels, mine would be 00Carter because of all the crazy action, suspense, and sci-fi stuff I've written for that - totally out of my element, but that's what makes it fun. I don't think I've ever had that feeling of "Haven't I written this before?" with that one LOL.