I had a very interesting (not necessarily in a good way) experience with one of my homeworks, which was to construct a simple theoretical model for a red giant. First of all, it was due about 2 weeks ago, but Jeremy (the prof) is so smart that he won't have any trouble marking it at any time (most people try to mark homeworks all in one go to get into the mindset). In any case, the deadlines are only 'suggestions' because no one really cares very much about the grade so long as the students are learning.

The reason I'm 2 weeks overdue is that the problem set is difficult, and I'm not the only one to discover this. I've spent several whole days trying to figure out the problem and I had to disregard some of the conditions set out by the question in order to solve the problem.

Then today I found out the probable reason why I was having so much trouble. Jeremy himself apparently hasn't bothered working out the answer for the question himself yet.