Teorema
I noticed striking similarities between this film and Teorema by Pier Paolo Pasolini. Both involve a group of upper middle class (arguably bourgeoisie) people who are extremely sexually repressed. A visitor comes along who stays with them for a little while. He sexually liberates each of them until they cannot stand their meaningless lives anymore and break free in unbridled catharsis.
Given that there are many differences in the details of the story, the structure of the two films is very similar. Elements of this kind of story are also present in Visitor Q by Takashi Miike.
Basic formula
Repression + Strange Visitor = Unrepression