Here are a few suggestions:
1. Squats: Stand with your feet shoulder-width apart. Bend your knees as though you're going to sit on a chair, keeping your weight on your heels. When your legs are parallel to where a chair seat would be, slowly rise to your original standing position. You can do this in front of a chair too....then if your legs get too tired, you can just sit in the chair.
2. Plié Squats: Take a wide stance with your toes pointing outward. Standing upright, slowly bend your knees in the direction of your toes until you can no longer see your toes. Slowly return to your starting position.
3. Wall Sits: With your back touching the wall, move your feet away from the wall so that the wall is supporting the weight of your back. Bend your knees so that your legs form a 90-degree angle. Hold as long as you can. (This one is challenging!!!)
4. Lunges: With your arms by your side, take a giant step forward with your right leg so your thigh is parallel with the floor. Pushing off the same leg, return to your starting position. Repeat with the left leg. (Traveling lunges are also an option.)
5. Calf raises: Holding onto a table or desk or chair for balance, raise your heels off the floor, then lower.
6. Gluteal squeeze: While sitting or standing, squeeze the muscles of your rear end. Hold, then relax.
7. Crunches: Lying on your back with your knees bent, reach for your knees, hold for two counts, then return to the floor.
8. Push-ups: You can do these on the floor or standing up using the wall. Push yourself up off floor or away from wall with your hands a little wider than shoulder-width apart.
9. Knee Raises: Lift knees toward chest.
10. March around your house lifting knees as high as you can.