When your fabulous-looking friend tells you she swears by something, your ears perk up a little bit, right? One of the cutest gals in the office here at Stuff We Love HQ recommends this slightly weird-looking, old-school fitness solution: Iron-core kettle bells, a hot new fitness trend that actually goes way back. Called girya in Russian, kettle bells were the weightlifting and toning weapon of choice for the Red Army. The basic kettle bell exercise couldn't be more simple—swing it upward while keeping your body weight centered in your heels—but when done correctly, it's a cardiovascular workout and a weight-training exercise in one. Looks a little goofy, but if our friend (or the Red Army) is any evidence, kettle bells seem to work. $29.99 at GoFit.net.