Fencing! It's a great workout, kind of like interval training (work your ass off for a bit, take a breather, then back to getting your heart rate up). There's the camaraderie of a team sport, but when you fence a bout, you're on your own.
Can be tough on the knees, especially épée, where your knees are part of the target area and you get stabbed in them. But both foil and saber fencing don't have knees as target. Can also be tough on the wrist, much like tennis. But it's great fun, and a good way of working out any anger one may have. It also tends to be pricey if you get into it (equipment isn't cheap), but most fencing clubs don't require you to have your own gear when you're starting out. Though a communal mask can be icky.
Can be tough on the knees, especially épée, where your knees are part of the target area and you get stabbed in them. But both foil and saber fencing don't have knees as target. Can also be tough on the wrist, much like tennis. But it's great fun, and a good way of working out any anger one may have. It also tends to be pricey if you get into it (equipment isn't cheap), but most fencing clubs don't require you to have your own gear when you're starting out. Though a communal mask can be icky.