For all their value at the graduate level, in which one often needs a few weeks just to get familiar with a topic before even being close to a position to think about a paper, semesters are generally horrible at the undergraduate level. At week twelve—I think that's where I am now—I have discussed as much about certain topics as either I can stand or—much more obviously—my students can. Of course, the autumn is especially bad with its dearth of breaks and its bunching of the one big break at the end.
There are things that can seem full of wonder in week one that by week nine or ten have lost their gloss except for those who are very committed. And, while I am very committed to all sorts of issues in, for instance, the debate between internalists and externalists about content, it can be much to expect students, especially those whose interests lie in continental philosophy—as most of mine do—or who have no general interest in philosophy at all.
Not just for them, but for me, the break cannot come soon enough.