1. NARROW PUSHUP -- 1 MINUTE                   
                   
                  We'll start with the
                   tough stuff: This
                   exercise will work
                   your chest,
                   shoulders, and
                   triceps (the muscles
                   at the backs of your
                   upper arms). Assume
                   a knees-on-the-floor, 
                   feet-crossed pushup position,
                   but move your hands together so your thumbs and
                   index fingers touch (as shown here). The space
                   between your hands should form a triangle. This
                   variation gives your triceps a better workout than a
                   basic pushup. (To further challenge yourself, use
                   your feet, rather than your knees, for support; to
                   ease up, position your hands under your shoulders,
                   a little wider than shoulder-width apart.) Complete
                   as many pushups as you can in 1 minute. It's okay to
                   rest when you need to. 

                   2. DOOR SQUAT -- 2 MINUTES
                   This exercise will tone your hamstrings (the muscles
                   in the backs of your thighs), quadriceps (the muscles
                   at the fronts of your thighs), and butt. First, open a
                   sturdy door (make sure it's firmly hinged) and loop a
                   towel around each knob. Hold both ends of the
                   towel in your hands. Stand with your arms fully
                   extended in front of you and your feet
                   shoulder-width apart. Keeping your back straight,
                   squat until the tops of your thighs are almost parallel
                   to the floor. Be sure to keep your weight firmly over
                   your heels. Now rise to the standing position. That's
                   1 repetition. Do a total of 20 repetitions. Next
                   spread your feet slightly wider than hip-width,
                   turning your feet so that they point slightly away
                   from each other. Now do 20 more reps. 

                   3. THE SUPERWOMAN -- 1 MINUTE

                   4. RUNNING IN PLACE/JACKS -- 1 MINUTE
                   Alternating a few sets of calisthenics with an aerobic
                   interval helps keep your heart rate elevated
                   throughout the routine. For this set of aerobic
                   moves, run in place for 30 seconds, then
                   immediately do 15 jumping jacks. 

                   5. REVERSE LUNGE -- 2 MINUTES 
                   This move will help firm your butt and legs. Stand
                   straight with your hands on your hips. Keeping your
                   left leg straight, step back with your left foot as far
                   as you can; then lower your left knee until it nearly
                   touches the floor, or as low as you can. Your right
                   knee should automatically bend to a 90-degree
                   angle. Lift yourself back into the starting position,
                   tightening your butt muscles as you go. Repeat 10 to
                   15 times with your left leg, then work your right leg. 

                   6. ONE-LEGGED CALF RAISE -- 2 MINUTES
                   Stand with your left forefoot on the edge of a step
                   so that your left heel hangs off the edge. Wrap your
                   right foot around your left ankle and grab a railing or
                   wall for balance. Rise up onto your toes, then slowly
                   lower yourself until your heel falls slightly below the
                   step. Repeat 12 to 20 times, then switch to work
                   the right leg. (If you don't have a step, you can just
                   lift yourself off the floor. This variation won't
                   challenge your calf muscles as much, so try holding
                   yourself in the raised position for a 2-second count.)

                   7. LATERAL RAISE -- 2 MINUTES 
                   Stand straight with your left hand on your hip and a
                   weight or heavy book (a dictionary, the phone
                   book, whatever) in your right hand. Slowly lift your
                   right arm out to the side until it's parallel to the floor.
                   Hold for a second, then slowly lower it back to your
                   side. Repeat 12 to 20 times, then switch sides. 

                   8. SHOULDER RAISE -- 1 MINUTE
                   Stand with your arms straight out from your sides,
                   parallel to the floor. Slowly rotate both arms
                   forward as if you were drawing 6-inch-diameter
                   circles with your fingertips. Continue for 30
                   seconds, then draw backward circles for 30
                   seconds. 

                   9. LEG LIFT -- 3 MINUTES 
                   This exercise targets the hamstrings and buttocks.
                   Get down on your hands and knees. Press your left
                   knee forward, then slowly extend the leg behind you
                   until it's in line with your back. Lower your leg
                   slowly, and again press the knee forward. Do 20
                   repetitions with each leg. 

                   10. CRUNCH -- 3 MINUTES
                   Start with a basic crunch to work your upper
                   abdominals: Lie on your back, knees bent, feet flat
                   on the floor, hands lightly touching the back of your
                   head, elbows out. Keeping your lower back
                   pressed to the floor, slowly curl your head and
                   shoulders up, then lower them back down. Do as
                   many repetitions as you can in 1 minute. 

                   Next, add a twist to work your oblique muscles: As
                   you lift, twist your upper body to bring your right
                   shoulder toward your left knee. Then twist to the
                   right, drawing your left shoulder toward your right
                   knee. Alternate from side to side for as many
                   repetitions as you can for 1 minute. Then work the
                   lower abdominals with reverse crunches. Lift your
                   knees so your shins are parallel to the floor. Then
                   slowly curl your knees toward your chest, pressing
                   your lower back into the floor and your navel
                   toward your spine. Lower again and repeat for 1
                   minute. 

                   11. COOLDOWN -- 2 MINUTES 
                   Completed that final rep? Don't just collapse onto
                   the couch and grab the remote. Cool down and
                   stretch first to keep your muscles from getting sore.
                   Start by walking for 2 minutes or so, until your heart
                   rate slows and your breathing returns to normal.
                   Finish with a few good stretches, like these: 

                   For your hamstrings: Lie on your back with your
                   left leg bent and left foot flat on the floor. Lift your
                   right leg straight up, clasp your hands behind your
                   right thigh, and gently stretch the leg toward your
                   chest. Repeat with your left leg. 

                   For your quadriceps: Steadying yourself against a
                   wall with your right hand, bend your left knee, grab
                   your foot with your left hand, and pull your heel
                   toward your buttocks. Stand as straight as possible
                   as you stretch. Repeat with your right leg. 

                   For your shoulders and arms: Clasp your hands
                   behind your back and draw your shoulder blades
                   together as close as is comfortable.

 by women.com, prevention.com
http://www.healthyideas.com/weight/buzz/20min/step2.html