Bunneez part 2 Epi-Compliant During Lily's 3rd year at Hogwarts, Ginny dies. After Harry mopes around for most of the year, the three Potter children get together to perform a ritual that will bring back the ghost of "the most beloved person," so Harry won't have to be so lonely. They are shocked when the ghost of Severus Snape joins their household.
Twenty years after the battle of Hogwarts, Snape, dressed in rags and not lucid at all, shows up at Harry Potter's door. Nobody knows how he survived or what he's been doing all this time.
Harry & Snape had a torrid affair during much of his school years; Snape's death left Harry bereft. Many years later, Harry discovers a spell to give the beloved dead a second chance at life, by putting the soul into a man's seed to impregnate a woman. Albus Severus is the reincarnation of Severus Snape, and Harry can't wait until he's old enough to tell the truth & re-establish their relationship.
Harry & Ginny's sex life includes times when he blindfolds her & polyjuices her into a man. One time, the blindfold slips, and she finds out she's Snape.
AU The Snarry Horror Picture Show: Dr. Snape-N-Furter seduces Harry Potter & Ginny Weasley who've shown up at the door of his castle hoping to use the phone.
Characters in a Harry Potter online RPG find some players are contradicting both books & movies & insisting on their own version of canon. They claim "Rowling got it all wrong" and "should've crucio'd the bint when we had the chance." It unfolds that Snape & Harry survived the war & ran off together, and Rowling met them in a bar during one of Harry's rare drunken binges.
Crossover w/House: Harry goes back to the Shrieking Shack to find Snape barely alive, and Portkeys to New Jersey to get him treated by the best doctor he can find.
Nonmagical: FBI agent Harry Potter is required to work with undercover agent Snape to overturn Voldemort's drug cartel, but Potter isn't sure which side Snape is really on.
Nonmagical: One of Harry's children is sick. The only person who might have a cure is the reclusive former Dr. Snape (he lost his license to practice medicine over some scandal years ago), who demands a very high price for even attempting to look at a patient.