At around half way through the semester we have some tests for our students. I'm doing a whole bunch of courses this year (including teaching Visual Basic - which has been interesting) and so I have to invent the quizzes. Each test has 25 questions with one correct and four incorrect answers.
That makes 200 wrong answers to be invented. Plus the sample tests as well. You might think that inventing wrong answers is easy, but actually it is a bit tricky. You have to have ones that kind of make sense, but are not right. If they are too right they are confusing, and if they are too wrong they are too easy.