The Ballad of Randy and Joan by Annie Sewell-Jennings
Summary: "She is a blank canvas, and he is not allowed to paint her."
Since that's not much to go on, it's set in a post-apocalyptic world (it's the end of the world as we know it) and Buffy doesn't remember her life before the world ended.
My Life Closed Twice by Annaross
Summary: Post-Not Fade Away. Buffy seeks Spike's remains, but then finds him in the most unusal place. Spike/Other, Spike/Buffy. Anaross says, "Not sure where this is going. But new fic. PWP--- Poetry without plot.

Well, no poetry yet."
And I'll pimp my own fic...
Playing Dirty by Noelle
Summary: Angel O'Toole enlists the help of his girlfriend, Buffy Summers, when his English professor, Spike Thompson, threatens his perfect GPA with bad marks. Spike is still recovering from the heartbreak of losing his fiancee, Drusilla, when Buffy comes into his life. Will Buffy stick to the plan or end up falling for her boyfriend's teacher?