A brisk 10-minute workout with a skipping rope can be as good an exercise as a 30-minute jog. You can use a length of clothesline (about 10ft/3m will do - measure it by stepping on the middle; the ends should come to about mid-chest).
For handles, tie a knot in each end of the rope and wrap plastic insulating tape 4-5in/100-125mm in front of each knot. At a pinch (but only if you skipped as a child and remember how), you can jump with a phantom rope - no rope at all.
Always skip on a carpet or mat, and always wear cushioned aerobic or jogging shoes with good arch support. Start with the rope hanging to the floor behind you, your arms angled out 6-10in/150-250mm from your hips. Twirl the rope forward from the elbows. Start skipping with your feet together; as you gain in skill, try alternate-foot jumps. Your feet should come only a few inches off the floor. For variation, lift your knees high in front or kick up high behind.
Skip for 30 seconds, then rest for 30 seconds. Do this ten times. Gradually increase the skip and rest times to 60 seconds each, for a total of 20 minutes, then gradually lengthen the total time until your heart rate is in your aerobic target range for 20 minutes.