[That Foreign Guy]

Squash is awesome, really gets you moving fast in all sorts of directions and is just plain fun.

Rock climbing, also great fun although finding a partner can be a pain in the ass - I suggest a place that allows bouldering.

Basically, whatever you enjoy the most is the best for you.

Edit - clicked the link, I stopped reading after "Old manners of getting in shape seem to us today as antiquated and inefficient as using Indian clubs and medicine balls." Erm, medicine balls can give you a great workout, I have no idea on indian clubs, but yeah, this article is badly written and pretty poor content too.