![](https://i.kinja-img.com/image/upload/c_fit,q_60,w_645/dkq334vjxxffutsgiirq.jpg)
When I was a kid we played Hi-Ball: four people on a single trampoline, throwing a pillow-like ball at each others’ goals over a net about eight feet high. It was a crazy workout, and a ton of fun, and who knows how many people landed wrong and broke a wrist? None of us did, but it wasn’t for lack of trying.