Depending on the grade level you are talking about, classroom rules can vary greatly. The most common are rules like "Don't speak out of turn/raise hand to talk" to "Show up on time for class." Some college and high schools may have a rule like "Attend to personal needs before coming to class." In other words, use the bathroom before class. You can find a fairly complete list at
. http://712educators.about.com/cs/backtoschool/a/classrules.htm.