This little workout covers all the basic human movements. It requires only one kettlebell and can be adjusted with reps, sets, and load to fit anyone. Don't let the simplicity fool you:
Test it first by doing 5 rounds with no rest between each exercise. Work up to 20 rounds. Twenty rounds equals 300 swings, 100 squats, and 60 push-ups. That's a respectable workout.
To make it harder, first increase the number of push-ups. Then, add a bigger kettlebell. This is a great workout anywhere, any time, and for any reason.