Buy a horse.
Take a few rudimentary lessons; enough so you know that the even that half-asleep 30 yr old lesson horse will still scare the sh*t out of you.
Then buy a horse.
Not a green stupid horse. An experienced broke, safe, smart, high energy, athletic horse. One that knows how to behave but knows damn well enough how to misbehave too.
Get on said horse.
Don't die.
Works like a champ.