Strapped for time? Try this workout by Ross Enamait, which is titled No Excuses. It will take exactly 10 minutes to complete, and there's no rest until you complete the entire 10 minute routine.
Pick 4 exercises. I recommend a full body movement, an upper body movement, a bilateral (both legs) lower body movement, and a unilateral (one leg ex. a lunge) lower body movement. You could also do a full body movement, upper body pull (pullup, chinup, inverted row, etc.), upper body push (pushup, military press, handstand pushup, etc.), and a lower body movement. In this example, Ross chose burpees, pullups, bodyweight squats, and pushups.
Begin with 60 second intervals of each exercise, then move to 45 second intervals, then 30 second intervals, and finish with 15 second intervals. So a sample workout would look like this:
First Round
- Burpees x 60 seconds
- Pullups x60 seconds
- Squats x60 seconds
- Pushups x60 seconds
- Burpees x 45 seconds
- Pullups x45 seconds
- Squats x45 seconds
- Pushups x45 seconds
- Burpees x 30 seconds
- Pullups x30 seconds
- Squats x30 seconds
- Pushups x30 seconds
- Burpees x15 seconds
- Pullups x15 seconds
- Squats x15 seconds
- Pushups x15 seconds
I completed this the other day when I was unable to make it to the weight room. It was more than enough to keep me going (mentally and physically) until the following day, and it is just one of many different workouts that one could perform when strapped for time.
Don't shortchange yourself. If you can't make it out to a training facility, or feel like you're strapped for time on a given day, don't allow yourself to settle for doing nothing. You'll be amazed at what you can accomplish in a mere 10 to 20 minutes!