Channel your elementary school days and skip yourself slim. You can burn over 100 calories in just 10 minutes, while at the same time sculpting lean arm and leg muscles. Best of all, a rope takes up no space, and it's easy enough to bust out and start jumping anywhere -- even while traveling. Alternate between your standard two-foot jump and running-in-place jump, varying your speed. If you're one of those exercisers who need a program to follow, try RopeSport’s workout DVDs (RopeSport.com).
Everlast Deluxe Speed Rope, $8, Amazon.com