I'd like to share my High Intensity Interval Training (HIIT) routine, which I do about 3 times per week. I found it on youtube: https://www.youtube.com/watch?v=cZnsLVArIt8&index=1&list=PLQw2RVJ0L4tML3Mj5tODujrwsqiVpYIgP

It consists of 4 exercises: flutter kick squat, high knees, burpees, jumping jacks.

Start of with a warm up, then move on to the following:

-60 seconds flutter kick squat
-no rest
-60 seconds high knees
-no rest
-60 seconds burpees
-no rest
-60 seconds jumping jacks
-20 seconds rest

This counts as one whole set. For the next set, do each of the exercises for 50 seconds (again, no rest in between and then 20 seconds after the whole set) and each time you do another set, drop it by 10 seconds.

For the final set, you will only do each exercise for 10 seconds so really squeeze and try as harrd as you can.

I really recommend this workout, it only takes about 15 minutes (use youtube video for timing)
and it really wears you out.

Not sure how many calories it burns, but my guess is about 250 kcal when you do the workout and because it's HIIT and adds some muscle resistance like squatting, I will continue to burn more calories even when you're done with the routine.

GOOD LUCK