Kettlebell
Credit: Photograph by Michael Pirrocco

Popularized in the U.S. by Soviet special forces trainer Pavel Tsatsouline, kettlebells are superior to dumbbells for two exercises: swings and Turkish get-ups, the best all-purpose core exercise ever invented. For the swing, Tsatsouline says, the off-set handle creates a longer lever arm than a traditional dumbbell would, allowing you to generate more speed and force.

Try: Turkish Get-Up 
Lie flat with a kettlebell held above you in your right hand, elbow locked and right knee bent to bring your foot closer to your body. Raise your torso up and to the left, to rest on your left elbow, always keeping the kettlebell straight above you. Push with your left arm and right foot until standing. Lie back down, continuing to hold that kettlebell in your upright arm. Repeat on the other side.