I'm going to ride a horse!
The local horse riding spot is eager to get you on a horse and riding because they make a little money from it and you have a great time.
A horse is a big animal who does pretty much what you want him or her to do within reason, and it is exciting to ride! Yee Hah!
I don't care if you are a city dweller living on the 23rd floor condo in Manhattan - horse riding is a great time. This Saturday is your day - Go ridin'!