Here are a few from the Rock Bottom Chuck Wagon Races held on Memorial Day Weekend in Arkansas. We're headed there this year to cover the event if any members are from this area, it's a very cool weekend event!!
http://rockbottomchuckwagonraces.com/
This was a horse race around the oval track, and rounding one of the turns the guys saddle strap broke and his saddle basically fell off which dumped him on the ground at a very high rate of speed!!!
Canon 1D and I think I had my ISO bumped way up to 800 on this one, dont have my hard drive hooked up with the original photo, and for some reason the EXIF data isnt on Smugmug?

Ranch Rodeo during the night time events! These are real cowboys who do this for a living. I was very impressed, and my wife was in love
Canon 1D ISO 200 70-200 f/2.8 lens

They have horse races where anyone can enter, and it costs like $20 to enter and the winner takes that pot. Well this young lady and her horse would win every time. On the second day, the event organizers tried to talk her out of entering because none of the Cowboys wanted to enter if she was going to. I guess they didnt want to be shown up by a young lady! I printed this out and gave it to her and she was the glowing she was so happy!!
Taken with a Canon 1D f/9 @ 1/400th of a sec ISO 200 - 70-200 f/2.8L Lens