When I was a student I found juggling to be a useful distraction when taking a break. It kept the mind engaged but took my focus completely away from my studie

When I was a student I found juggling to be a useful distraction when taking a break. It kept the mind engaged but took my focus completely away from my studies. I think this the key to a good break activity. You want to stay sharp but completely distract yourself. There are probably also benefits that come from using your motor skills, different parts of the brains and even shifting your focus to follow moving objects. It was also quite rewarding to slowly see myself improving.