This would make a great procedure (Harry Wong). Count to five or hold up one finger at a time when the class needs to refocus. Discuss what occurs for each number at the beginning of the school year and eventually the reaction will be automatic.
Stop the Interrupting! Blurt Alert cards-This freebie consists of 3 different sets of "blurt alert" cards. The basic premise: each time a student interrupts you or blurts out, hand them a card and keep talking