Work your butt and thighs by trying a side lunge, and add a press with weights to work out your shoulders. This exercise effectively tones and tightens your total body. Stand tall with your feet slightly apart, three-to-ten-pound weights at head level, and palms facing forward. Take a giant step left into a lunge, raising the weights over your head. Push off your left foot and return to start. Repeat to the right.