Make games out of the stuff
Just musical chairs on a large scale set up poles on the ground they can park the horse in between when the music stops and have them work on a skill to get out of the stall (turns,backing up, practice two point etc)
Take down a 'stall' each turn anyone who doesn't make it into a stall just goes large until the game is over so it works better with a smaller group
I like doing things like around the worlds and sisors.This helps kids with balence and makes it fun!
In my class we practice patterns by going around rails and doing "horse science" on paper and my instructor quizzes us on things before we do our "ride at will" at the end of class which is basically doing whatever we want that's not too dangerous. When we warm up we do exercises like toe touches, arm swings, "pour your pitcher" (leaning forward) and "drop your anchor" (leaning back) just saying lol