Have the group stand in a circle. Determine a throwing pattern around the circle. For example, 1 throws to 4 who throws to 2 who throws to 5 who throws to 3 who throws to 1 again. Start with one ball and practice the pattern. After the group has mastered one ball, introduce a second ball by having two people start throwing at the same time. Then move on to three, four five up to however many people there are in the group. Once you have a large number of balls being juggled it creates the illusion of a very complex feat!