I have something awesome for you, and I think the timing is just right for testing season! Go Noodle is a website that is full of "brain break" videos for your kids. The kids just watch and follow along. There are videos that are appropriate for all ages, and you can choose energizing or calming videos. Each video is 3-5 minutes long. I think this would be great for getting everyone to wake up first thing in the morning, or when they seem to be drifting.
Here is a screen shot of some of the videos you might choose.
And here is a video of some our 5th graders experimenting with a brain break this morning. They seemed to enjoy it.