Looks like this is going to be a good documentary, here are some interesting facts:
http://www.rubberroommovie.com/

http://www.facebook.com/pages/The-Rubbe ... 716?ref=ts

Why are people put there?:

Excessive lateness
Excessive absence
Sexual misconduct with a student
Overly forceful student discipline
Perceived incompetence as a teacher
Physical or verbal abuse towards a student
Accusations of impropriety by a student
Accusations of impropriety by a colleague
An unrelated criminal conviction
Illicit drug use
Unpaid parking tickets