There is Lamardeuse's amazing story A Taste of Liberty, which is a crossover with Harry Potter and where Mysterious Marylin is a real wizard Seer as well as an old friend of Snape. The plot is, Harry is tired of being the hero and, after having read an issue of Rage, decides to fuck off to Pittsburgh to get laid. Dumbledore sends Snape to get him back to Hogwarts.
Seriously, give it a shot even if you don't like the pairing (HPSS), because there is humor, angst, a good plot, an appearence by almost all the QAF cast (not only BJ), action,... and it's long and well-written ! Everything to please (if you love/like/can stand HP) ^^

Here is the link: http://lamardeuse.dreamhost.com/hp/tasteofliberty.html