Here’s a well-done Harry Potter fan film called Severus Snape and the Marauders, which the makers of this crowdfunded fan film describe thusly:
Snape, Lily and The Marauders have graduated Hogwarts School of Witchcraft and Wizardry. At a local pub, James Potter and his friends reminisce about their last seven years, and contemplate their future. All seems bright for these four friends despite the darkness that awaits them, until Snape arrives. Thinking about the war they are to join and the part Snape might play, James decides to do something about Snape once and for all.
[via Geek Art Gallery]