Move It was created by Australian teacher Jarrod Robinson to encourage physical activity. After you install the free extension to your chrome browser you are given the choice to set how much time between brain breaks (in five minute intervals up to an hour). What occurs next is the true magic of this extension. As you are working on your Chrome browser, the extension will interrupt your work by opening a new tab that gives you a quick physical activity to do (run in place for 15 seconds, do 10 jumping jacks, etc.). You can not go back to your other tabs until you click the word Done, then you are right back where you started.
Check it out in this video, or install the extension in the Chrome Web store.