To work the imagination.
The group (any size) stands in a circle. One person starts saying “I have a basketball” (or whatever type of ball they choose). They must pretend to pass the ball to someone else in the circle as if it were that type of ball.
For example, if you have a bowling ball, you could pretend to roll it across the circle; a tennis ball, you can pretend to serve it; a basketball, you can bounce-pass it, etc.
The person receives the ball still pretending it is what the first person said (i.e. if it’s a ping pong ball, they catch it very easily in one hand. If it’s a bowling ball, they bend over to pick it up, struggling with its weight, etc) They then pick a new type of ball and pass it to a new person. Continue on until you can’t think of any more types of balls.