We run through showmanship patterns without a halter. He has to walk, trot, lope beside me and change gaits as I do (well, mine is more speed changing). He has to stop and square up without me touching him, and pivot as well. Backing up is interesting, especially keeping him in a straight line. :P
We play a lot of games. He's really big into "racing" me. We start at one end of the arena and I run as fast as I can to the other end. He'll keep pace until about 20 feet away and then get to the fence first.
I also make him "mirror" my movements. It basically looks like he's cutting me. I'll dart one way and then switch to the other way and he has to gather me up.
We play a lot, mostly racing because he LOVES it.
Biggest thing for me, though. Is that no matter where he is in the arena, if I stop he MUST come back to me without a voice or movement other than me halting. People watching think that's crazy, but if I am just standing still in the middle of the arena he makes sure to come to me (walking, jogging or loping).