Get a Rubbermaid step stool tool box, about 13" high. Use it as a step: Step up-up, down-down but Slowly because otherwise you might miss and/or fall off. Use weights while you're stepping, either delt lifts, bicep curls, or just resting on your shoulders...I like that because the weights help my balance. Vary the steps, too: up-down on one side, then the other. You can do lots of variations.
Roundhouse kicks from kickboxing work well, too. Get into form by squatting, then pull you left foot in to your right heel so it's pointing to your left side and SLIGHTLY forward. This will also bring your right hip forward a little and up. Keep your hands curled in fists, protecting your face. Bring your right knee up, which will cause you to shift your balance to your left leg and lean slightly forward. Kick forward from behing with your right leg, keeping your foot relaxed, not pointed. The leg will travel in a circle to the full extension. Bring it down. Repeat on other side.
That's not a very good description...I can demonstrate better than I can describe, but I bet you can find pictures in a fitness magazine.
Plies also work: Feet slightly wider than shoulder-width apart, bent your knees over your feet but don't go past your toes, squeeze your butt to come up. Keep your pelvis tucked under and your back straight.
Jennifer Lopez, eat your heart out