Don't forget about jump rope

I know, I keep posting about cardio exercises.  I can't help it, I need all the inspiration and new ideas to get motivated, so I figured you do too.  I love jumping rope as a cardio exercise, and over time you'll be surprised at how long you can do it.  I like to do 100 jumps at a time, which can take 1-2 minutes.  If you have a short rest in between sets, you can do this for 10, 15, 20 minutes, and really get your heart rate up and your leg muscles burning.  You can really mix it up and vary your jumps; side to side, front to back, knees up, double dutch, heel taps, etc.  Couple this with some time on a machine and your cardio workout just became more diversified and interesting.