What strategies does the teacher use to actively engage the students? How effective are these?

I saw several examples, just today, on how the teacher engages the students.
-Today they had a sort of extended recess/field day for about an hour with a few different classes. I noticed right away, that the teacher started playing with the kids. He played 4-square, basketball, soccer, jumprope, scooters, etc with them. I thought that was really admirable, because he could have just sat and watched, but he wanted the kids to be active, so he joined in. I found it to be very effective, and the kids LOVED playing with him.
-The teacher is also very good at validating the children. As we walked to the library, he commended several of the children on being quiet and respectful. I saw that this was not just effective on the behaving students, but the more rowdy ones saw his praise and started to follow suit.
-The teacher also has been reading a chapter book to the kids. I've noticed that he is very good at changing his tone for different parts of the story, and also asking questions as they go along. He doesn't just read straight through, he will read a paragraph or so, and then ask, "why do you think the character is doing that?" or "what do you think will happen next?" He even had each table discuss two different characters and why one did what was right, and the other didn't. This helps the students have better comprehension to what they are reading, and become more interested in the story.