If you have a few hours (or a week) to spare, check out TVTropes’ section on Fan Fiction.
“If you want something done right, do it yourself.
Fan Fiction is a form of Alternate or Expanded Universe created by the fans of a work, rather than the work’s original creator. Fan Fiction, or “Fan Fics” as they are often called, are written for several reasons: To continue a story that ended prematurely, to see what would happen if certain characters are placed in unusual situations, see what happens when the characters of one franchise encounter the characters of another franchise. Or sometimes to get get the characters to have mad passionate (or occasionly just mad) sex with each other.”