"My Immortal?" Yeah. It's out there. It's also got its own TV Tropes page.
I'm not much into fanfic, but back years ago, I read the Stargate Heliopolis archives fairly regularly. One of my favorite stories from there was "Have Yourself a Manic Little Christmas"– a minor Goa'ud servant of Apohpis arrives on Earth around Christmas time, and decides to overthrow the local System Lord and install himself as the ruler of Earth. He assumes all the veneration for this "Santa Claus" figure means he's identified the ruler of the planet, so he sets out on a mission to kill Santa Claus. Cue SG-1 to save Christmas. It's a lot of fun, and captures the spirit of the show well. It was also an author challenge response, so it took a ton of really, really stupid ideas and worked them into a very good story.
