I've been an admirer of Stacy Westfall for some time. She's a horse trainer in central Ohio who is probably most noted for her bareback, bridleless riding in reining competion.
Below is a video of Stacy riding the black Quarter Horse mare known as Roxy, without saddle or bridle, at the 2006 All-American Quarter Horse Congress.
Pretty amazing, aren't they?
If you'd like more information on Stacy and her training techniques, check out her website here.