Every now and then, I get a student who attempts to dominate the classroom...speaking first and out of turn, bringing negative attitudes out, bringing up off topic discussions, and challenging just for the sake of challenging. This is the type of student that I have the most difficulty in dealing with. They seem to be putting on a kind of front...not for my benefit... but to establish him/her self as dominant in the classroom. Any suggestions on how to deal with this type of dominator?