Many times, we come across one-off lectures from famous Computer Scientists. Last year, I came across one by Ms. Barbara Liskov, but I could not go because the University Hall was bit far. Tomorrow, there is one by Dr. Knuth! Now the problem I am facing is, "I don't know much about the material he is going to talk", so I am not sure if I should plan and I fear it will be like going for a "temple". :) What is your advise and general strategy that you have followed whenever you wanted to attend a talk or lecture wherein, it may have been worthwhile if it were an introductory tutorial, but instead you were sitting in an advanced 1 hour lecture by a famous scientist.