It gets their brain working fast. It is a break they can do on their own. It is also very challenging.
It's called Finger Aerobics
Here it is:
Lift both hands with four fingers up on each hand.
Move the pointer on one hand and the pinkie on the other.
Now move the tall finger on one hand and the ring finger on the other.
Next move the ring finger on one hand and the tall finger on the other.
Now move the pinkie on hand and the pointer on the other.
Keep doing this over and over to make a rippling effect.
This forces both sides of your brain to work together.
Try this for 30-40 seconds.