Before the web, kids mostly plagiarized an encyclopedia but most commonly cliff's notes. Every time I caught someone, I got asked, "How do you know?" So, in 1994 when I had a huge stack of plagiarized first papers, I said, let me read these anonymously and you can tell me when you know.
I would read along and people yelled out when they realized but I never made it down a whole page. One was copied from the textbook, a place we decided that I would not have any real knowledge of and that I would not look. That was a big hit. Of course my favorite, was the time I got to the second word (not in vocabulary books then) zeitgeist and the whole class yelled now.
I pointed out if they could figure them out and they had indeed it looks like I could too.
Two kids gave me virtually the same paper at least four times. I would bring them in after school and ask student 1 who did the writing to adopt Nancy Reagan's approach to drugs, and "just say no." I also pointed out that every time we had a paper the first thing I did was pull theirs and put them side by side. I suggested that Student 2 who spent all of my study halls diligently doing HIS OWN math adopt the same approach with my class, especially since I kept catching him. I suggested at best he should write his own paper and at worst, get another person's so it would be more of a challenge for me.
People wonder why I stopped sending papers home and made them do them all in class. For two reasons is my answer: it is harder to cheat and you have to write longhand or print on the AP tests and if you don't practice that with all the typing we now do it will be hard.
More of these stories later....