When I was younger, we lived out in the country and there werent any other children in my area to play with, so I spent a LOT of my time pretending, and of course playing with my dogs.
One thing that I had 'turned' into a horse was a LP tank. It was HUGE, and wide, and tall. I used a towel for a saddle, rope for reins and had to use a step stool to get up on it. lol. We even had a prairie next to our house, so I would even pretend that I was a horse, and used to run around there.
Our neighbors had horses, so I spent a lot of time under an old oak tree next to their pasture. I could never get the horses to come up to me tho, but it wasnt for the lack of trying, thats for sure. lol