I'm guessing that I was one of the last to see Lion King (my sister and I saw it today). Anyway, while I was simply in awe of the performance, I noticed that there was alot of physics at work. The giraffes (stilts and all) needed to keep their center of mass over the support area of the stilts. The center of mass would have been a little below the actor's actual body, and further up (closer to his chest) because of the long headdress. The stilts need to be spread out to ensure a greater support area to bear the center of mass. If the actor had altered his cetner of mass in any way, he would most likely not be able to stand (or he'd fall)...

The hammock can support up to four people because of the tension in the ropes connected to the two trees. The tension equals the force of the person's (my sister) weight. The tension isn't able to keep the hammock completely straight, so there is always the dip in the strings. The system itself is fairly stable until either the ropes wear down and no longer can take the weight and force of the people using the hammock, or the trees connected to the hammock also can't support it. When someone uses the hammock like a giant swing, their motion becomes a part of a vertical circle. At the bottom of the swing, the force is the greatest.