At my university, the MS and PhD programs in Computer Science have comprehensive exams. The exams retest the student on topics from designated core courses. The exams are separate from the course and may be written by a group of instructors instead of just the instructor who taught the course.
Students are given a list of books to read. Some of the books indicate selected chapters, others are expected to be read and understood cover to cover. The scope of the exams is daunting and preparation for the exams is expected to be a major undertaking by the students taking months of preparation. For full time students this is difficult. For part time students like myself who work full-time and have family this effectively sidelines research during the preparation period. If you do not pass the exams on your first try, it can be very demoralizing.
I was able to stay motivated by following the strategy I described in a similar question: strategy
What other strategies have people used?