This year I took all three courses on Black-box Software Testing. Each of them means an investment of four weeks of my time, usually up to 2-4 hours per day. This was quite a blast, and I am happy that I made it through the courses.
One thing that stroke me in the first course was the different uses and misuses of code coverage discussed in the first part, the Foundations course. Here is a short description of things I have seen working, and not working so much.