I had the opportunity to attend a real voodoo ceremony in Togo (West Africa) a few years ago. It was a very interesting experience, and very hard to describe. You can find videos of them on Youtube. It consisted of a mixture of dancing, which at times got extremely energetic almost to the point of violence (blood was spilled), and weird magic tricks. For example, at one point the shaman buried a bag of broken glass in the ground which later was dug up again and had turned into a bag full of coins. It went on for a very long time. Despite the fact that there were was a substantial audience of Western tourists watching, it didn't feel like a performance. The participants were not focused on the audience at all. On a number of occasions, some of the dancers nearly collided with some audience members.
If you ever get an opportunity to see an authentic non-touristified voodoo ceremony, I recommend it. I've never seen anything remotely like it before or since.