But you really must go read Elves, Gremlins and Eskimoes by beer_good_foamy.
Don't worry. It's not slash. There are no hot naked vampires.
There is, however, a completely unimaginable crossover. He crossed Angel season 5 (the season they were at Wolfram & Hart) with the Simpsons. Yes, you read that correctly. Simpsons characters & Angel characters interacting in a completely believable and entertaining way.
There are 5 parts written so far. I have no idea how many it will eventually be, or how long until it's done. But you should go read it anyway.