I ran across a sorta Dear Abby thing for college sex and relationships and there was a letter to “Alice” about a daughter discovering that her father has been cheating on her mother. She’s asking Alice how to confront him about it. She gives good advice.
It reminds me of a good friend’s discover that his stepfather had some pornography on the family computer. He devised the perfect plan in that he would set a slideshow screensaver to that folder right before dinner. When the screensaver kicked on, he figured his Mom would look aghast at him and then he would look aghast at his stepdad.
He never did it, of course. His stepfather was extremely uptight, but that was preferable to his licentious father. But the possibilities of using a screensaver to bust him were quite endless.