I started a new classroom management technique in my classroom this year that worked quite well! I only use it on days when I can feel that the class vibe is off. That usually means pep rally days, before holidays, and on full moons! :)
I created this board for my class:
How I use Mystery Student
I have all my students' names written on slips of paper and separated into holders by block (These are magnetic IKEA holders that I Gorilla Glued tacks to). At the start of class I will choose one name randomly and tack it next to the sign. As class goes on, I write the names of disruptive or off task students on the board. At the end of class I reveal who the mystery student is, and if their name is not on the naughty list, the whole class gets a piece of candy or sticker. It is surprising how much middle school kids love stickers! Students also encourage each other to behave and stay on task because not only do they want the piece of candy, they don't want to be the reason that EVERYONE misses out.
How I use Mystery Time
I also have a bunch of random times written on slips of paper. These time range from 36 seconds to around 5 minutes. At the start of each class I choose a random time and tack it next to the sign. Anytime someone in the class is off task, I start a timer that I have around my neck. I don't say a word, I just hold the timer and keep it going until everyone gets back on task. At the end of class, I reveal the mystery time and what the total time on my stop watch is. If they have not gone over the mystery time, the class gets a piece of candy or a sticker. One thing that really bothers me is when other kids "Shush" one another, so I have a rule that I automatically add 10 seconds for each "Shush" that I hear, but that might not bother you!
I usually use just one or the other, but on particularly rough days I will use both mystery student and time. If I use this technique, I make a big show of it at the start of each class. Since I use it rarely, it is still a big hit and quite helpful on rowdy days!