1. Buffy is really hurt by some vampires or demons or something, LOL, and she almost dies. Spike comes back from Africa, finds her, and takes care of her.
2. Spike comes back, but he completley avoids Buffy. She knows he is back, and avoids him in the beginning too. But soon she starts to miss him insanely, and she gos to him and they get back together.
I will think of more later ;)