If you get injured - modify, heal and regroup. If you get busy - plan out a schedule. If you get distracted - focus your attention on your goal. If you get demotivated - come back to us. Even if you have to slow down to a crawl - do not give up. Forward momentum, no matter how slow, is always better than standing still.
I love when you can use your own workout equipment, such as a flight of stairs. While I don't, or won't do some of the other exercises they suggest in this article, such as jumping jacks, there are plenty of things you could substitute for that. The idea, is to use what you have for a good workout.