Jet-ski riding is an activity that can be enjoyed by anyone, and doesn't require you to leave the ground. Well, actually, you do leave the ground, but you trade it for water, rather than launching into the heights. All the fun of a motorcycle, but with no cars, traffic lights or hard pavement to spoil your ride. All you need is a sense of adventure and a willingness to get wet.
Your first ride will be with an experienced jetski instructor, but if you are interested, later on you can try it on your own!
The biggest danger is that you will like it too much and you won't want to stop! In the future training, you can try more interesting tricks and flips and enjoy quite high speed!