I know what you mean. I didn't know when the concert here would be when I bought the tickets. Now since last wednesday I know when the exams will be and I don't write one in the week after the concert (I will be at home anytime monday morning and then I should stand up at 6). Believe me, I'm damn happy about that but a friend who also goes to the concert writes an exam. She's gonna pretend that she's ill and ask for another date to write it.