The first thing I do (especially if the kiddo isn't normally one that acts up) is to try and establish why that students is "having a day." There can be many factors for behavior, and something likely happened before they came into my room. I can usually pinpoint the problem and talk through it rather quickly and stop the behavior. If that doesn't work, then the horn goes up first. If they continue to be a problem, the go face the wall by the door. This doesn't happen often, and I greatly dislike sending students to the office. 99% of the time, the relationships we have built up with students will make it super easy to take care of problems.