I've had a few different jobs there. Mostly acrobatics, which is sort of like extreme gymnastics. I did mostly aerial performance - so it's like doing tricks and stunts in the air, for example with a large swing very high off the ground. Jumping from it and catching each other. Or walking across a wire. I think people like the feeling of adrenaline they get by watching.
But they did get to see me fall one day. I got hurt and haven't been able to do it anymore. I tried for something else, but it turns out I didn't really like it.