I disregarded a warning from the travel consultant Xstrata uses and I went directly to the largest Carnaval celebrations in the DR. There were some awesome costumes (each representing a group of some sort (mainly local companies), some good beer and awesome music. The constumed monsters carry around a heavy ball on a rope that they will hit you with it (anywhere below the belt). It really does hurt; the only rule is that you cannot add weight to the ball, thats it, anyone is game.
The spiders shown above were an especially agressive gang.