Do you ever get tired of hearing the dreaded question we get asked a million times a day..."May I use the bathroom?!"
The best decision I ever made was buying a small magnetic dry erase board and hot glueing it on a wall as a form of classroom management. I printed these cards and laminated them. I then made a magnet for each student with their class number on it and placed them under the "I'm in the classroom" heading.
Throughout the day, as long as I am not in the middle of teaching, students may freely go to the restroom, etc, without asking me! It is so nice! The student simply moves his or her number underneath the correct heading before leaving the classroom, and returns it when they get back. The students know there is only one boy and one girl allowed in the restroom at a time, so it helps hold them accountable. It also allows me to see where my students are at all times with just a quick glance.