You might have noticed the recent resurgence in Kettlebells over the past few years in a gym near you. But make no mistake, they aren't some new trick or gimmick. Kettlebells have in fact been around for decades and are used by the Russia's Sptetznaz (Special Forces) as standard fitness training devices. What's so neat about them is that they not only build strength (like traditional weights), but they also build core (think Pilates), balance, and cardio endurance. Best of all, you can get a full workout in under 45 minutes!

For more information, you can check out the following:

Kettlebell Exercises

Mike Mahler's Aggressive Strength

Athletes.com