(Updated: All my words under the pictures went away, damn blogger!)
The Denver Post has a good write up of what all it involves, so go read over there real quick and then come back.
(drums fingers on table, digs piece of junk out of teeth)
Oh hi, you're back, great! Pretty cool, huh?
I scanned in some pictures from the program that are very cool and show a bit of the artistry between the horse and humans. They even have their own musicians to play while the performance goes along to match the tempo of the horse.
It is truly spectacular, go see it if it comes to your neck of the woods!