YES! Time outs! I had forgotten I used to have to do that sometimes too. As you say, put one in the bedroom and close the door. I would set the timer in the kitchen because I would get busy and forget someone was locked away cooling off! That and water squirt bottles have helped.

When I had a few young ones at the same time, they would all start dashing around and things went flying - vases, picture frames. Then the time outs were really for ME, to calm down, clean up, etc.