This will be very helpful for a middle school classroom. I feel that students that age tend to speak before they speak and having this in the classroom will encourage students to "think" before they speak.
Kids love to decorate their rooms and this is something that they can get excited about. 10 little plastic birds stickers in beautiful translucent colours that will alight on 10 wire stickers that they can place anywhere they want on their windows.
Math bulletin board-by now your students should learn the number of ways you can say a problem or ask for a solution - this is a fun way to do that. First have them choose or you choose one of the four operations, then have them show you which of the quadrants applies to that operation and have them select one of the words within the quadrant and use it properly in a problem.