My pony would always head straight for the freezer (where we keep our grain), and he'd open it! It was so bad, since he's also a very good escape artisit, I've had to put a lock on the bottom of his door so he can't open it lol.
My friends x-racer would shake his head up and down all the time, he would grind his teeth, stick his tounge out sometimes while shaking his his head lol. He was a funny boy, he also drank out of a tim horton's coffee cup lol.
While he was at a diffrent barn, he was in for 23 hours of the day so he would stand with his head in a corner, and then he'd lift one back leg up, and proceed to bob his head lol.
He stretched alot too when she'd go to bridle him