If I had to choose, I'd go skydiving. I am afraid of falling, so someone would have to push me, and someone would have to go with me, because I'd be too afraid that my parachute wouldn't work. In the event that I didn't have a working parachute, at least I would hit the ground hard enough to pretty much die on impact, which is a lot less scary than just hitting it hard enough to break every bone in my body, as with bungee jumping.