Movement in the classroom: two techniques

We have long, 75-minute periods at my school. I like to do a lot of discussion, but it's hard to stay focused for 75 minutes straight, so one of the things I struggle with is getting the students up and moving about for at least once in a class. I want to get them moving, but do so in a way that is educationally useful. Today I used two techniques to get my students up and moving in class, and they seemed to be pretty effective:

1) Clickers. You know, the "personal response system"? I've used clickers in the past for checking student understanding. Today, inspired by this article about the experiences of a physics professor at Harvard, I decided to use them also for movement. Students were given a multiple choice question as usual, but when there was disagreement about the correct answer, students had to get up, move about the room, talk with the other students, and try to convince them their answer was correct (or, of course, be corrected by the other students). Some students were very fact-based; others were more open and interpretive. Overall, the technique combined movement with a very student-directed form of learning--they needed to convince the other students of the correct answer--and because I reminded them to use the reading, it was also evidence based.

2) Agree-Disagree. I ask a question, and have students move to one side of the room if they agree, the other side if they disagree. We're studying Gandhi, so today I asked them a couple of questions about the use of violence: "If someone hit you, would you hit him back?" and "Would the Indians have been better off if they used violence against the British?" Because many students switched their position for the two questions, it gave us a chance to discuss use of violence in a personal vs. political matter, as well as the specifics of the Indian situation.

Overall, students seemed engaged, particularly considering it's the last day before spring break! So they're probably techniques worth returning to.