I'll get you started with mine:
Dante: -While at a show, he was untying every horse in sight, so I stuck him in our gooseneck stock trailer. He must've got bored, so he climbed into the hayloft space at the front of the trailer. (There's a picture in his profile thing of him up there, too.)
-I left the back door open on the cab of my truck, and he climbed into the back seat for the treat bag.
Bandit: -First day of being introduced to his little two-wheeled cart that he would eventually pull, and he decides to climb into the footspace on the cart.
-He is totally a kleptomaniac. He steals things and wanders off with them before anyone notices or just plays keep-away. He once leaned over the fence, into my convertible, and stole the rear-view mirror (it was broken off the window and awkwardly strapped up with duct tape.). I haven't found it yet.
2-Pak: -There's a paved road running down the hill above our farm, and I ride down it some days. If 2-Pak has shoes on and gets bored/lazy/whatever is going through his head, he plants his front hooves and propels himself along with his back legs, making little sparks and horrid screeching noises with his shoes all the way down that hill until I make him stop.
-He is scared to death of the color pink, particularly bight pink. If someone is wearing something pink, he'll lay his ears to the side and snorts at them, and won't come within ten feet of them until "The Evil Pink Thing" is removed or covered.
Magic: While practicing barrels once, she knocked over a barrel, and usually I have her keep going, but for some reason she had to stop and inspect the fallen barrel for a bit. I tried to get her to go again, and she just turned her butt to it and kicked it into the fence. (It was *obviously* the barrel's fault that she knocked it over. It jumped in front of her! )
Ruby: While trail riding with a friend, we came across a dead raccoon on the side of the road. My friend's horse snorted at it and wouldn't leave it alone, and Ruby just sorta stared at them. My friend's horse suddenly squealed and struck out at it with its front hoof, and Ruby backed up a few steps, then did the same thing. Now whenever she comes across a dead raccoon she *must* "punish" it, or else the trail ride cannot go on.
Tanner: When we first got them, Tanner and Magic would panic if they couldn't see eachother. The two of them were standing in the pasture, a few feet from eachother. My dad pulled up in his truck and parked between them, and the two went on grazing for awhile, until Tanner picked up her head, looked around, and suddenly started squealing ind whinnying like she does when she can't find Magic, but she wouldn't move from where she was standing. Then Magic came around the truck and bit her.