I spent most of my time looking like this:
I guess the name for it is belay. I was responsible for being on the other end of the rope and making sure the kids were safe by holding onto the rope and lowering them down. I learned how to tie some special double 8 knot very well as I got them ready to climb.
There was also a place for bouldering and some of the munchkins tried it. It's a shorter wall you climb up sans rope.
Have you done rock climbing? What is your favorite kind? Any tips?