China Lake (1989)

Edmond, a compulsive TV-watcher, and his apathetic son Scooter live in a caravan in the Nevada desert. One of the highlights of Edmond's life is when he acquires a new zapper for his satellite TV set. Eighteen-year-old Scooter's one and only leisure pastime consists of occasional visits to a bar where nothing ever happens. One day they are visited by fat Aunt Edna and Scooter's teenage sister Laura. Edna prevails on Edmond to pull himself together. And Scooter and Laura get to know each other and decide to head off to Las Vegas together, where a faintly incestuous tension develops between them.