A NU 1L's guide to sitting in on a class when you're visiting:
1) Read this page.
Don't know what to pick? Pm me or another student a time slot and we'll tell you what 1L class to pick.
2) It's week 8 of the semester. You don't need to warn the prof that you aren't a student. They know who we are by now. Sit in the back, and if you're in a student's seat, we'll move you, trust us.
3) On the day of, report to admissions and tell them what you are doing. The dude in there will say sure, go right ahead. I assume he knows when classes are cancelled somehow.
4) Don't be late, don't make noise, dear god don't ask a question, dress nice so we have something to look at. We're already tired of looking at each other.
Compared to all the other schools I visited, Northwestern seems to be a lot more laid back about visiting classes. Some schools want to usher you to the best profs, but our admissions office has better things to do.
Okay my casebook misses me.