I got a kettlebell. Multiple friends and other sources have been praising the benefits. So I tried it last week at the gym. It hurt so good. But then, reading up on it, this sentence clinched the deal for me:
The basic movements, such as the swing, snatch, and the clean and jerk, engage the entire body at once, and in a way that mimics real world activities such as shoveling or farm work.
I bought it from here, because they were the ones with the simplest, most classic design. It really is pretty.