A variation on the classic lunge, curtsy lunges are a great way to tone your glutes and legs.
How to do it: Start standing with your feet hip width apart, and then, keeping your weight in your left foot, take a big step back with your right leg, crossing it behind your left leg (as if about to do a 'curtsy'). Slowly bend your knees and lower your body straight down until your front thigh is parallel to the floor, and both knees are bent at 90 degrees. Be sure to keep your abs drawn in and your back straight. Do 15 reps on one side, and then 15 reps on the other.
Form tip: As you lunge, keep your front knee right over your ankle and don’t let it roll in or out, your toes should point straight ahead.