Most of what I do has been covered, but one other thing my campers have always loved was "What IS That?" you send them one at a time into the tack room to pick out a piece of equipment that they have no idea what is or what it's for, then you let everyone take a guess. "Prize" to the one that gets the closest. (we used mini snickers or dumdums) Then you explain what it is, and even show them if you can. This is also great for rainy days, because it ties up time, and you don't have to plan anything special to do it.
"Keep a leg on each side and your mind in the middle"