Pairs elect 'dropper' (A) and catcher (B) and stand facing one another - within arms reach.
The idea is for (A) to hold the ball in two hands, then randomly drops it. (B) - who starts with hands in the air - must catch using quick reactions.
Obviously it's easier the higher the ball is dropped from, so start higher, then progress so the ball is being dropped from merely 40cm or thereabouts from the ground.
After 30 seconds, swap roles.
