Quiet room

A room that is quiet. A silent room. An enclosed space with no sounds. 
This may be used for people that feel: overstimulated, anxious, stressed, etc. 
It could be an effective way for a person experiencing the previously mentioned to relax and feel better.
A quiet room may be most effective if it contains things that are of comfort or liking to the user of the said 'quiet room'.
They can spend certain time in the said room doing things that the person considers calming activities.
If you're ever stressed, consider trying the quiet room method to see if it's of any help to you.