Stand in front of a sturdy chair* (make sure it won't slide out from under you) and place your left foot in the center of the seat. Step up onto the chair and bring your right knee forward and up. Lower yourself back to the floor, with the foot landing quietly. Switch legs, and repeat. That completes two steps. Do 20 steps total.
Squats! Do 3 sets of 10 squats before each meal. While squats target your quads, they also activate your core and just about every muscle in your lower body, including your glutes, hamstrings, and calves.