Here is a quick leg workout you can do anywhere. Start out with 8 repetitions of each move and increase the number of reps after a few weeks or as soon as you don't feel the last rep of each exercise is challenging.
Squat - Stand with your feet slightly wider than hip-width, turned slightly outward. As you lower your hips the knees bend and will start to shift forward slowly. Try to prevent your knees from traveling too far forward past the toes. Keep the abdominals engaged and try to keep your back flat (do not tuck the tail or arch the low back). Continue to lower yourself until your thighs are parallel or almost parallel to the floor. Keep the knees aligned with the second toe and body weight evenly distributed between the balls and heels of both feet. Exhale and return to start position by pushing your feet into the floor through your heels.
Reverse Lunge - With the feet about hip-width apart, slowly step backwards with the left leg. After the left foot hits the ground push back into the right hip to slowly lower the left knee towards the floor while keeping the chest raised towards the ceiling. Press the right foot into the ground and think about pulling the right knee backwards while swinging the left leg forward to return to standing.
Sumo Squat - Stand with your feet wider than your shoulders, toes are pointed outward about 45 degrees. Lower your upper body, with abs engaged and a flat back, bending your knees.
Standing Side Leg Lifts - Stand with your abs engaged and transfer your weight to your right leg (keep knee soft) then lift your left leg out to the side as high as possible. Slowly return to the starting position. Complete the desired number of repetitions, then repeat the exercise with your right leg.