I used to ride every saturday (a rented horse) when I was in high school...after the army is when I bought the horse, but due to being a teaching assistant and going to graduate school, I had to sell him after 2 years. There aren't any more stables that rent horses in or near Philadelphia, but on vacations I'd always find a stable to ride one.
An interesting note...when we rented a cottage in the Poconos (PA) on Keen Lake, I found a stable and rented a horse. I told the guide about the horse I owned, which I'm sure he thought was only a story, so he gave me the most spirited horse in the stables, thinking I'd make a fool of myself. Much to his suprise, I did really well, and he told me in all the days of renting out that horse, I was trhe ONLY ONE to be able to keep him under control!
Sir John