Depending upon how much you each are taking, there a a thousand things you can do. There are challenges. Grab a single playing card and at any time, fling it to another. If they manage to catch it, they have the privelege of flinging it when they wish at someone else. You can stalk each other in the dark, see how close you can get to another person without their realizing you are there. You can play "leave your personality behind" sit in a circle with the others, and at a leader's command everyone move to the seat on their left, but leave yourself in your original seat - so that the new person assumes your ego and senses. You can challenge each person to get from one place (where ever they currently are) to another without touching the floor. You can have one another attempt to control the movements, or actions or thoughts of another in your group.