Pretty simple, just describe the plot of a film in such a way that the villain comes off as the hero and vice versa, allowing the next person to guess what movie it is you're talking about. I'll start with an easy one: A visitor from another world attempts to obtain a simple piece of jewelry in order to secure the survival of his race and feed his millions of children, but is maimed and murdered by a cloak and dagger organization that oppresses aliens and brainwashes the citizens of their own planet.
Oh, for Pete's sake, "Men in Black"! How about this: eccentric, superstitious physician has a drastic, medically-unsanctioned treatment for a East European immigrant with a rare dietary disorder.
Alcoholic man in his 40s hangs around 12 year olds and lets them handle his wood while he gets them drunk.
A radio executive who worked his ass off to get to New York City has his life turned upside down by a punk.