If you demonstrate tacking him up, someone is going to want to ride him. I don't think you want to give pony rides to all your classmates.
I find that people who are not familiar with horses tend to be fascinated with seeing their hooves being cleaned out. I will assume since you are bringing your horse around newbies that he has excellent ground manners. So that is something you can have a lot of people try, picking up your horse's front foot, and using a hoof pick/brush.
You can also bring in photos off the internet of the consequences of improper/nonexistant hoof care, bring in different sized horseshoes (can hold up to horse's hoof to compare size/shape/which ones would or would not fit), and general info about keeping hooves healthy.
Last edited by Skipsfirstspike; 05-19-2011 at 10:05 PM.