If you are limited to a small work space, try this workout on for size.
What You Need:
Set of Dumbbells
You will work through each exercise for 1 minute of repeated effort, then rest for :30 seconds. A minute is a long time, so pace yourself to keep moving the entire time. Choose a weight that is light enough to continue doing reps, but not that you need to keep taking breaks. Goal is to get heart rate up, muscles burning, and not need a large space. The intensity of your jog/run will determine how high your heart rate gets. Focus on breathing and not holding your breath.