I also took an idea that we used there and have implemented it in my own classroom. We have something called the "Wonderful Necklace," and it hangs on a hook near the reading corner in our room. Anyone is welcome to take it, just as they take a work out, but they take it to a friend and tell them, "I think you're wonderful," and ask permission before putting the necklace around their friend's neck. The recipient can either pass it on when they have finished wearing it, or can return it to its place.
The goal is to facilitate the passing on of kind words and compliments - just because.
If you have tools that you use in your peaceful classrooms, I would love to hear about them!
*From my internet research, it seems that this song is by Red Grammer, from an album called Teaching Peace. You can stream it on youtube here: http://www.youtube.com/watch?v=QPg7i9nIEf0.