A technique I use a lot is to use software to put students in random groups, then have them do active learning activities in those groups. These activities are sometimes the "conceptest" technique created by Mazur, or think-pair-share. My set of conceptest activities for freshman calc are here (click through to "active learning resources").
The conceptest technique involves showing a conceptual, multiple-choice question. Students think silently for a minute or two, then vote. (I have them hold up 1 finger for A, 2 for B, etc.) If there is a clear consensus for the right answer, we discuss it briefly and move on. If not, then students discuss it in groups. The theory is that the right answer is supposed to "win" in debate. Then we vote again.
Although this technique can be done without having students get up and move, I find that having them move around like this helps a lot. If I don't assign groups, then inevitably many students will not participate in discussion. If I try to assign permanent groups, then we get problems because of absences.
In this technique, often there will be situations in which, e.g., everyone in group 2 initially votes for C, while everyone in group 3 votes for A. In this situation, I swap some students between groups so that each group will have something to debate.
If I'm doing several of these questions, I usually also re-randomize the groups between questions. This is optional, but it helps, for example, with situations where one group is composed entirely of weak students. That group doesn't have to languish and keep failing.
The reasons for doing all this don't necessarily have anything to do with getting blood flowing or reducing boredom, but it certainly also has that effect, and students seem to appreciate that. I think it also creates a nice social atmosphere in the class, because everyone knows everyone else, and they all know they need to maintain good relations.