This is a variation of an activity we used to do at the rock face and sometimes inside the gym. Instead of a rock or a climb in hold, fill a plastic bottle with water. The size of the bottle will depend on how strong you are. If it has an unusual shaped like a milk bottle it will add to the challenge. Toss the bottle from one hand to the other and try and catch it with just the fingertips of your hand on a downward motion. Add spin to the bottle, for more of a challenge. Highly recommend you do this outside, especially with old milk bottles as they tend to explode on impact with the ground. If there are more than one of you in your bubble at home, you could toss the bottle between you, trying to catch it with just your fingertips.