Here are the top 5 cheat stories I've seen my friends involved in...
5) You know how some people take the PSAT in high school? This is also the test that qualifies you for National Merit Scholarships if you do well enough. I myself was only a Nationally Commended Scholar because my score fell 2 points short of the minimum criteria. Anyway, it was well known that two of my friends (they were gf and bf) were sitting right next to each other during that exam, and that the guy cheated off the girl on it. As a result, they got the same selection index score. I always thought it was kind of unfair that someone got a National Merit Scholarship from cheating and I fell two points short on my own steam. Eh, bygones.
4) I once saw two people blatantly cheating off each other's midterms in a class during my junior year in undergrad. They were tapping each other's feet and pointing at certain questions on their exams, and obviously copying each other's answers. However, these two people did get caught by the professor when he graded their essay answers. It was especially noticeable apparently since they copied each other's grammatical mistakes.
3) Another high school story: senior year, AP biology. The teacher was gone on a doctor's appointment on the day of a test, so the substitute teacher administered the test. According to what the students said, the guy came in from the beginning announcing that he didn't care what they did and if they wanted to look in their books that was fine with him. One of my friends took it into his head to go one step better: he went into the teacher's desk, found the answer key, and wrote all 50 answers on the board. The entire class cheated as one, which was really stupid, since it was fairly obvious that many people who normally got 40/100 suddenly got 85/100. The other stupid thing was that they didn't seem to consider that someone would rat on em, in a class of 35. Everyone knows there are always 1 or 2 who crack under the pressure of their consciences and go sobbing to the teacher. That particular friend got kicked out of every school society he was a member of, and the school started some kind of proceeding against him. All I know is that he suddenly stopped appearing at school for a while.
2) One of my best friends wasn't doing too hot in her Spanish class in undergrad, so she traded finals with one of her other friends. He took her Spanish final for her, and she took his bio final for him. Doesn't seem like a fair trade-off does it? But she's a bio whiz, so it waasn't too hard for her.
1) Another one of my best friends. He's never taken a computer science class before, but he knows a lot of stuff just from having tinkered around with computers for fun. One of his friends was failing a computer science class, and begged my friend for help. No questions asked, my friend went and sat in on the final and took it for the guy. The result: he scored the highest grade on the final in the entire class of 376 people. The guy never got caught, which I thought was amazing, because I think it looks at least somewhat suspicious that someone goes from semi-failing grades to the highest score on the final.
Note: I wonder at the laxness of the security during law school finals. Someone could come in and take a final for someone else, since they don't even check your ids, and no one knows all the other people in the class, so who would realize if there was a stranger in their midst?