So, let's get to it: A total-body, no-equipment-necessary workout that should (theoretically) last you 20 minutes. My guess, however, is that you'll come in a few minutes over because you'll want to factor in rest/water breaks. Still, this is a do-anywhere, quick-and-dirty type of workout.
The rules: Five exercises, one minute each, repeated four times through. Reps don't matter, get yourself through the minute at a pace that works for you and while doing each exercise with proper form. Breathe deeply through each exercise, and hydrate. AND (obviously) warm up and cool down.
Ready? Top row first, left to right, then bottom row. Left to right.
1) Wall Kicks: Stand facing a wall, hands on the wall. Tap the wall with your feet, alternating (of course). Kind of like toe-taps on a BOSU, if you know what that is.
2) Pushups with Slow Froggers: Perform your pushup, and when you hit plank position at the top, bring your right knee up to your right elbow. Return to plank, repeat with your left knee, then do another pushup and repeat.
3) Around the Clock Lunges: Start forward with your right foot, lunge to 12:00. Back to start, then out to 3:00. Hit 6:00, then hit it again with the left food and make your way back up to 12:00.
4) Dead Man Burpees w/Jump: This is a regular burpee, except you fall flat to the floor after you pop out to plank position. Pick yourself up to plank, pop in to squat, jump up and repeat.
5) Sprinter Crunches: Think knee to elbow, upper body halfway up to a full sit-up position.
If you need further descriptions for any of the above exercises, please let me know. I'd be happy to expand in the comments below if necessary. As always, exercise at your own risk. What's shown above may or may not be appropriate for your personal fitness levels. Use sound judgement whenever you try a new exercise and, if necessary, consult your physician for further advice.
Question: What is your favorite bodyweight exercise?