Having covered this topic in my first year, I return to it now having noticed that people whom I presume to be current 1Ls are googling for information about Columbia Law's Barristers' Ball. Everything I know:
1) If you want to go, buy your ticket early as they may sell out.
2) It is more formal than a regular party, but you don't have to wear a tux. If something is called a "ball," attending in casual clothes is inappropriate, and I say this as one of the worst dressed and groomed people in the law school. Thank God UVa and Columbia no longer expect students to wear suits to class (well, and now let in women).
3) Though a date is not required, this can be a good opportunity to introduce someone you're dating who's not in the law school to many of your friends and acquaintances at once -- and more to the point, to introduce them to your non-barrister significant other, so The Loudmouth in Contracts and The Guy Who Saved My Torts Grade will have faces matched to their descriptions.
4) Between the DJ and the crowd, the main room of Low Library gets too loud for conversation; if you want to talk to people, please retreat to the back room instead of trying to scream over the music.
5) Don't drink so much you throw up. That stopped being cool ... OK, it never was cool, but at least when you couldn't drink legally and therefore didn't get to drink often enough to know your limits, it was excusable. Unless you are the rumored 19-year-old of the class, you won't be excused.
And in the unlikely event that the New York Sun shows up again, don't talk to the reporter because they'll apply the same nonexistent journalistic standards to a social event that they do to everything else.