Hall Pass recorder to be kept in the classroom on a clipboard near the door. Students record when they leave the room so you have documentation (especially useful if anything happens in the bathroom, you know if your student may be responsible)
Bathroom pass, each student gets one sheet per semester 5 passes on the sheet. That's all the passes they get for the semester. This forces students to choose wisely when to use the restroom. If they run out and it is an emergency, I allow them to go, but they must make up lost time after school (generally 10 minutes). I print these on neon colored paper and always sign in ink.