In regard to the person who wrote asking how to meet other grad students: I'm in my second year in GSAS and it's a real problem!! Especially for people new to New York -- so many of the other graduate students are from the area and already have their network of friends in place. A few things I have discovered:

(1) For GSAS students, the afternoon tea in 301 Philosophy is a good bet. A lot of people seemed to be buried in their reading, but if you manage to strike up a conversation, you'll find that the book or magazine is a smoke screen for their real reason for being there -- which is identical to yours.

(2) Lunch in the cafe at Avery Hall is heavily frequented by grad students.

(3) Unlike other universities that I've been to, Columbia students seem to use the library exclusively to read, not to socialize -- but people do go to the periodicals reading room in Butler to get away from their studies. I found it's a good place to get to know people I vaguely knew from classes but had never talked to.

(4) Volunteering!! Community Impact (in Earl Hall) has lot of volunteer programs, which are a good way to get to know people in schools other than your own (as well as having lots of other benefits). Hope to see you around!!