Particularly wonderful things he said...
"Class, do you agree or disagree?" (Looking around at the students for a thumbs up or down, waiting until he had a response from everyone)
"Who can help _____ out?"
"I think I'm going to call on _____, you have been raising your hand patiently."
A student said to him, "I don't understand" and his response was, "tell me what you don't understand," and then they worked through the question.
"Class, let's all clap for _____, he/she did a great job on that problem." (Class claps)
I also got to be a student. I raised my hand, was called on, and purposely wrote the wrong answer on the whiteboard. The kids (and student teacher) loved that I was wrong and enjoyed correcting my mistakes.