Here we go...
5 Minute Warmup (any light warmup exercise that gets you to break a sweat)
5 Circuits of:
-- 60 seconds jumping rope at quick pace
-- 30 seconds doing normal burpees (no jumping)
-- 30 seconds shadow boxing (non-stop punching)
That's a simple, "full body" 15-minute workout that will get your heart pumping big time and leave you huffing, puffing, and sweating. It will not, however, leave you feeling like crap. Within 10 minutes of recovery time you should feel just fine and, probably, even a little energized and refreshed!