This week's challenge, taken from my 30-Day Fitness Challenge involves some of my favorite things: An exercise ball, interval training, upper body strength and chocolate. Well, not the chocolate, although you can always have a little - I'll never know.
Active Challenge: Sit on an exercise ball for at least 15 minutes today. You can do this while working, watching TV, reading, etc. If you don't have an exercise ball, spend 15 minutes standing rather than sitting at some point during the day.
Exercise Challenge Part one: Do at least 20 minutes of interval training. Begin with a warm up, then increase your intensity (either by going faster, higher or increasing resistance) so that you're at a level 5-6 on the this perceived exertion scale. Stay there for 3 minutes, then increase your intensity to Level 7-8 for 1 minute. Alternate 3 minutes at Level 5 with 1 minute at Level 8 for 20 or more minutes.
Exercise Challenge Part two: Basic upper body. Either before or after your cardio (or at a different time today), perform 2-3 sets of 10-12 reps of the following upper body exercises, using enough weight that you can ONLY complete the desired number of reps.
Pushups
Chest Press
Back Extension on the Ball
One-Arm Row
Seated Overhead Press
Skull Crushers
Bicep Curls
You can find details as well as substitutions for these moves at this Upper Body Progression Workout.
Nutrition Challenge: Drink water with every meal. If you usually have a soft drink or some other beverage with your meals, challenge yourself today by having water instead.
Remember, you can always create your own challenges if these don't work for you. How could you challenge yourself today? Think about it and then leave a comment and tell us about it.

Stability balls are such a tremendous thing to incorporate into any workout plan. They are great for recruiting the core and add variety to any routine. I use them constantly.