• The person performing this drill should kneel with the knee farthest from their partner on the ground and be turned sideways to their partner.
• Have your buddy perform a medicine ball chest pass to your outstretched arms.
• Brace your core and resist the rotation as you catch the medicine ball.
• Use your core to twist your body (keeping your arms relatively straight) and fire the medicine ball back at your partner. Bonus points if you knock him over.

Don't have friends? Try this one:

• Place your body to the side of a wall.
• Using your core, powerfully rotate and throw the ball into the wall.
• Brace your core and catch the ball as it comes back, resisting rotation.
• Pro Tip: Make sure the wall is reinforced and not drywall so you don't piss off your local gym owner.

Although these drills can be performed at any point during your workout, I'd recommend doing them before strength training. The force production will get your nervous system fired up and ready to lift heavy.